Merging upstream version 127.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

97 files changed, 1941 insertions, 2069 deletions

diff --git a/widget/ClipboardWriteRequestParent.cpp b/widget/ClipboardWriteRequestParent.cpp
index 751befbe05..8a05c6a194 100644
--- a/widget/ClipboardWriteRequestParent.cpp
+++ b/widget/ClipboardWriteRequestParent.cpp
@@ -27,7 +27,9 @@ ClipboardWriteRequestParent::ClipboardWriteRequestParent(
 
 ClipboardWriteRequestParent::~ClipboardWriteRequestParent() = default;
 
-nsresult ClipboardWriteRequestParent::Init(const int32_t& aClipboardType) {
+nsresult ClipboardWriteRequestParent::Init(
+    const int32_t& aClipboardType,
+    mozilla::dom::WindowContext* aSettingWindowContext) {
   nsCOMPtr<nsIClipboard> clipboard(do_GetService(kCClipboardCID));
   if (!clipboard) {
     Unused << PClipboardWriteRequestParent::Send__delete__(this,
@@ -35,8 +37,9 @@ nsresult ClipboardWriteRequestParent::Init(const int32_t& aClipboardType) {
     return NS_ERROR_FAILURE;
   }
 
-  nsresult rv = clipboard->AsyncSetData(aClipboardType, this,
-                                        getter_AddRefs(mAsyncSetClipboardData));
+  nsresult rv =
+      clipboard->AsyncSetData(aClipboardType, aSettingWindowContext, this,
+                              getter_AddRefs(mAsyncSetClipboardData));
   if (NS_FAILED(rv)) {
     Unused << PClipboardWriteRequestParent::Send__delete__(this, rv);
     return rv;
@@ -57,12 +60,12 @@ NS_IMETHODIMP ClipboardWriteRequestParent::OnComplete(nsresult aResult) {
 IPCResult ClipboardWriteRequestParent::RecvSetData(
     const IPCTransferable& aTransferable) {
   if (!mManager->ValidatePrincipal(
-          aTransferable.requestingPrincipal(),
+          aTransferable.dataPrincipal(),
           {ContentParent::ValidatePrincipalOptions::AllowNullPtr,
            ContentParent::ValidatePrincipalOptions::AllowExpanded,
            ContentParent::ValidatePrincipalOptions::AllowSystem})) {
     ContentParent::LogAndAssertFailedPrincipalValidationInfo(
-        aTransferable.requestingPrincipal(), __func__);
+        aTransferable.dataPrincipal(), __func__);
   }
 
   if (!mAsyncSetClipboardData) {
diff --git a/widget/ClipboardWriteRequestParent.h b/widget/ClipboardWriteRequestParent.h
index 6027661bdb..73dcc98192 100644
--- a/widget/ClipboardWriteRequestParent.h
+++ b/widget/ClipboardWriteRequestParent.h
@@ -27,7 +27,8 @@ class ClipboardWriteRequestParent final
 
   explicit ClipboardWriteRequestParent(ContentParent* aManager);
 
-  nsresult Init(const int32_t& aClipboardType);
+  nsresult Init(const int32_t& aClipboardType,
+                mozilla::dom::WindowContext* aSettingWindowContext);
 
   IPCResult RecvSetData(const IPCTransferable& aTransferable);
   IPCResult Recv__delete__(nsresult aReason);
diff --git a/widget/GfxDriverInfo.cpp b/widget/GfxDriverInfo.cpp
index d60b023ddc..4deafa5ad0 100644
--- a/widget/GfxDriverInfo.cpp
+++ b/widget/GfxDriverInfo.cpp
@@ -358,6 +358,77 @@ const GfxDeviceFamily* GfxDriverInfo::GetDeviceFamily(DeviceFamily id) {
     case DeviceFamily::IntelMobileHDGraphics:
       APPEND_DEVICE(0x0046); /* IntelMobileHDGraphics */
       break;
+    case DeviceFamily::IntelGen12:
+      // Rocket Lake
+      APPEND_DEVICE(0x4C8C);  // rkl_gt05
+      APPEND_DEVICE(0x4C8A);  // rkl_gt1
+      APPEND_DEVICE(0x4C8B);  // rkl_gt1
+      APPEND_DEVICE(0x4C90);  // rkl_gt1
+      APPEND_DEVICE(0x4C9A);  // rkl_gt1
+      // Alder Lake
+      APPEND_DEVICE(0x4683);  // adl_gt05
+      APPEND_DEVICE(0x4693);  // adl_gt05
+      APPEND_DEVICE(0x4680);  // adl_gt1
+      APPEND_DEVICE(0x4681);  // adl_gt1
+      APPEND_DEVICE(0x4682);  // adl_gt1
+      APPEND_DEVICE(0x4688);  // adl_gt1
+      APPEND_DEVICE(0x4689);  // adl_gt1
+      APPEND_DEVICE(0x4690);  // adl_gt1
+      APPEND_DEVICE(0x4691);  // adl_gt1
+      APPEND_DEVICE(0x4692);  // adl_gt1
+      APPEND_DEVICE(0x4626);  // adl_gt2
+      APPEND_DEVICE(0x4628);  // adl_gt2
+      APPEND_DEVICE(0x462A);  // adl_gt2
+      APPEND_DEVICE(0x46A0);  // adl_gt2
+      APPEND_DEVICE(0x46A1);  // adl_gt2
+      APPEND_DEVICE(0x46A2);  // adl_gt2
+      APPEND_DEVICE(0x46A3);  // adl_gt2
+      APPEND_DEVICE(0x46A6);  // adl_gt2
+      APPEND_DEVICE(0x46A8);  // adl_gt2
+      APPEND_DEVICE(0x46AA);  // adl_gt2
+      APPEND_DEVICE(0x46B0);  // adl_gt2
+      APPEND_DEVICE(0x46B1);  // adl_gt2
+      APPEND_DEVICE(0x46B2);  // adl_gt2
+      APPEND_DEVICE(0x46B3);  // adl_gt2
+      APPEND_DEVICE(0x46C0);  // adl_gt2
+      APPEND_DEVICE(0x46C1);  // adl_gt2
+      APPEND_DEVICE(0x46C2);  // adl_gt2
+      APPEND_DEVICE(0x46C3);  // adl_gt2
+      APPEND_DEVICE(0x46D0);  // adl_n
+      APPEND_DEVICE(0x46D1);  // adl_n
+      APPEND_DEVICE(0x46D2);  // adl_n
+      // Tiger Lake
+      APPEND_DEVICE(0x9A60);  // tgl_gt1
+      APPEND_DEVICE(0x9A68);  // tgl_gt1
+      APPEND_DEVICE(0x9A70);  // tgl_gt1
+      APPEND_DEVICE(0x9A40);  // tgl_gt2
+      APPEND_DEVICE(0x9A49);  // tgl_gt2
+      APPEND_DEVICE(0x9A59);  // tgl_gt2
+      APPEND_DEVICE(0x9A78);  // tgl_gt2
+      APPEND_DEVICE(0x9AC0);  // tgl_gt2
+      APPEND_DEVICE(0x9AC9);  // tgl_gt2
+      APPEND_DEVICE(0x9AD9);  // tgl_gt2
+      APPEND_DEVICE(0x9AF8);  // tgl_gt2
+      // Raptop Lake
+      APPEND_DEVICE(0xA780);  // rpl
+      APPEND_DEVICE(0xA781);  // rpl
+      APPEND_DEVICE(0xA782);  // rpl
+      APPEND_DEVICE(0xA783);  // rpl
+      APPEND_DEVICE(0xA788);  // rpl
+      APPEND_DEVICE(0xA789);  // rpl
+      APPEND_DEVICE(0xA720);  // rpl_p
+      APPEND_DEVICE(0xA721);  // rpl_p
+      APPEND_DEVICE(0xA7A0);  // rpl_p
+      APPEND_DEVICE(0xA7A1);  // rpl_p
+      APPEND_DEVICE(0xA7A8);  // rpl_p
+      APPEND_DEVICE(0xA7A9);  // rpl_p
+      // DG1
+      APPEND_DEVICE(0x4905);
+      APPEND_DEVICE(0x4906);
+      APPEND_DEVICE(0x4907);
+      APPEND_DEVICE(0x4908);
+      APPEND_DEVICE(0x4909);
+      break;
     case DeviceFamily::NvidiaBlockD3D9Layers:
       // Glitches whilst scrolling (see bugs 612007, 644787, 645872)
       APPEND_DEVICE(0x00f3); /* NV43 [GeForce 6200 (TM)] */
@@ -651,6 +722,7 @@ const nsAString& GfxDriverInfo::GetDeviceVendor(DeviceFamily id) {
     case DeviceFamily::IntelKabyLake:
     case DeviceFamily::IntelHD520:
     case DeviceFamily::IntelMobileHDGraphics:
+    case DeviceFamily::IntelGen12:
     case DeviceFamily::IntelWebRenderBlocked:
     case DeviceFamily::Bug1116812:
     case DeviceFamily::Bug1155608:
diff --git a/widget/GfxDriverInfo.h b/widget/GfxDriverInfo.h
index a584c7ac3f..0e1ba5c02d 100644
--- a/widget/GfxDriverInfo.h
+++ b/widget/GfxDriverInfo.h
@@ -181,6 +181,7 @@ enum class DeviceFamily : uint8_t {
   IntelKabyLake,
   IntelHD520,
   IntelMobileHDGraphics,
+  IntelGen12,
   NvidiaBlockD3D9Layers,
   RadeonX1000,
   RadeonCaicos,
diff --git a/widget/LookAndFeel.h b/widget/LookAndFeel.h
index 13219ff54b..2300f51388 100644
--- a/widget/LookAndFeel.h
+++ b/widget/LookAndFeel.h
@@ -92,8 +92,6 @@ class LookAndFeel {
     TreeScrollDelay,
     // the maximum number of lines to be scrolled at ones
     TreeScrollLinesMax,
-    // What type of tab-order to use
-    TabFocusModel,
     // Should menu items blink when they're chosen?
     ChosenMenuItemsShouldBlink,
 
diff --git a/widget/PuppetWidget.cpp b/widget/PuppetWidget.cpp
index 07b22d9a2b..7da6de3eaa 100644
--- a/widget/PuppetWidget.cpp
+++ b/widget/PuppetWidget.cpp
@@ -900,17 +900,14 @@ void PuppetWidget::SetCursor(const Cursor& aCursor) {
     return;
   }
 
-  bool hasCustomCursor = false;
-  Maybe<mozilla::ipc::BigBuffer> customCursorData;
-  size_t length = 0;
-  IntSize customCursorSize;
-  int32_t stride = 0;
-  auto format = SurfaceFormat::B8G8R8A8;
   ImageResolution resolution = aCursor.mResolution;
+  Maybe<IPCImage> customCursor;
   if (aCursor.IsCustom()) {
-    int32_t width = 0, height = 0;
+    int32_t width = 0;
+    int32_t height = 0;
     aCursor.mContainer->GetWidth(&width);
     aCursor.mContainer->GetHeight(&height);
+
     const int32_t flags =
         imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY;
     RefPtr<SourceSurface> surface;
@@ -928,22 +925,17 @@ void PuppetWidget::SetCursor(const Cursor& aCursor) {
       surface =
           aCursor.mContainer->GetFrame(imgIContainer::FRAME_CURRENT, flags);
     }
+
     if (surface) {
       if (RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface()) {
-        hasCustomCursor = true;
-        customCursorData =
-            nsContentUtils::GetSurfaceData(*dataSurface, &length, &stride);
-        customCursorSize = dataSurface->GetSize();
-        format = dataSurface->GetFormat();
+        customCursor = nsContentUtils::SurfaceToIPCImage(*dataSurface);
       }
     }
   }
 
   if (!mBrowserChild->SendSetCursor(
-          aCursor.mDefaultCursor, hasCustomCursor, std::move(customCursorData),
-          customCursorSize.width, customCursorSize.height, resolution.mX,
-          resolution.mY, stride, format, aCursor.mHotspotX, aCursor.mHotspotY,
-          force)) {
+          aCursor.mDefaultCursor, std::move(customCursor), resolution.mX,
+          resolution.mY, aCursor.mHotspotX, aCursor.mHotspotY, force)) {
     return;
   }
   mCursor = aCursor;
diff --git a/widget/ScrollbarDrawingGTK.cpp b/widget/ScrollbarDrawingGTK.cpp
index 3e0cad9179..9262667dcb 100644
--- a/widget/ScrollbarDrawingGTK.cpp
+++ b/widget/ScrollbarDrawingGTK.cpp
@@ -116,10 +116,7 @@ bool ScrollbarDrawingGTK::PaintScrollbarThumb(
 }
 
 bool ScrollbarDrawingGTK::ShouldDrawScrollbarButtons() {
-  if (StaticPrefs::widget_non_native_theme_enabled()) {
-    return StaticPrefs::widget_non_native_theme_gtk_scrollbar_allow_buttons();
-  }
-  return true;
+  return StaticPrefs::widget_non_native_theme_gtk_scrollbar_allow_buttons();
 }
 
 void ScrollbarDrawingGTK::RecomputeScrollbarParams() {
diff --git a/widget/Theme.cpp b/widget/Theme.cpp
index 15bf68ec01..fcfea14175 100644
--- a/widget/Theme.cpp
+++ b/widget/Theme.cpp
@@ -767,11 +767,11 @@ void Theme::PaintMenulistArrow(nsIFrame* aFrame, DrawTarget& aDrawTarget,
   const auto direction = [&] {
     const auto wm = aFrame->GetWritingMode();
     switch (wm.GetBlockDir()) {
-      case WritingMode::BlockDir::eBlockLR:
+      case WritingMode::BlockDir::LR:
         return PhysicalArrowDirection::Right;
-      case WritingMode::BlockDir::eBlockRL:
+      case WritingMode::BlockDir::RL:
         return PhysicalArrowDirection::Left;
-      case WritingMode::BlockDir::eBlockTB:
+      case WritingMode::BlockDir::TB:
         return PhysicalArrowDirection::Bottom;
     }
     MOZ_ASSERT_UNREACHABLE("Unknown direction?");
@@ -1099,9 +1099,6 @@ bool Theme::CreateWebRenderCommandsForWidget(
     const mozilla::layers::StackingContextHelper& aSc,
     mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
     StyleAppearance aAppearance, const nsRect& aRect) {
-  if (!StaticPrefs::widget_non_native_theme_webrender()) {
-    return false;
-  }
   WebRenderBackendData data{aBuilder, aResources, aSc, aManager};
   return DoDrawWidgetBackground(data, aFrame, aAppearance, aRect,
                                 DrawOverflow::Yes);
@@ -1208,6 +1205,7 @@ bool Theme::DoDrawWidgetBackground(PaintBackendData& aPaintData,
     case StyleAppearance::Textarea:
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
       PaintTextField(aPaintData, devPxRect, elementState, colors, dpiRatio);
       break;
     case StyleAppearance::Listbox:
@@ -1435,6 +1433,7 @@ LayoutDeviceIntMargin Theme::GetWidgetBorder(nsDeviceContext* aContext,
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Listbox:
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
@@ -1503,6 +1502,7 @@ bool Theme::GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
     case StyleAppearance::Textarea:
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Listbox:
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Menulist:
@@ -1678,6 +1678,7 @@ bool Theme::ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::MozMenulistArrowButton:
     case StyleAppearance::SpinnerUpbutton:
     case StyleAppearance::SpinnerDownbutton:
diff --git a/widget/ThemeColors.h b/widget/ThemeColors.h
index 739a7ca0f0..0e0fd044bb 100644
--- a/widget/ThemeColors.h
+++ b/widget/ThemeColors.h
@@ -62,7 +62,8 @@ class ThemeColors {
   explicit ThemeColors(const nsIFrame* aFrame, StyleAppearance aAppearance)
       : mDoc(*aFrame->PresContext()->Document()),
         mHighContrastInfo(ShouldBeHighContrast(*aFrame->PresContext())),
-        mColorScheme(ColorSchemeForWidget(aFrame, aAppearance, mHighContrastInfo)),
+        mColorScheme(
+            ColorSchemeForWidget(aFrame, aAppearance, mHighContrastInfo)),
         mAccentColor(*aFrame->Style(), mColorScheme) {}
   virtual ~ThemeColors() = default;
 
diff --git a/widget/android/GeckoTelemetryDelegate.h b/widget/android/GeckoTelemetryDelegate.h
deleted file mode 100644
index 43b20d4ad6..0000000000
--- a/widget/android/GeckoTelemetryDelegate.h
+++ /dev/null
@@ -1,100 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef GeckoTelemetryDelegate_h__
-#define GeckoTelemetryDelegate_h__
-
-#include "geckoview/streaming/GeckoViewStreamingTelemetry.h"
-
-#include <jni.h>
-
-#include "mozilla/java/RuntimeTelemetryNatives.h"
-#include "mozilla/jni/Natives.h"
-
-namespace mozilla {
-namespace widget {
-
-class GeckoTelemetryDelegate final
-    : public GeckoViewStreamingTelemetry::StreamingTelemetryDelegate,
-      public mozilla::java::RuntimeTelemetry::Proxy::Natives<
-          GeckoTelemetryDelegate> {
- public:
-  // Implement Proxy native.
-  static void RegisterDelegateProxy(
-      mozilla::java::RuntimeTelemetry::Proxy::Param aProxy) {
-    MOZ_ASSERT(aProxy);
-
-    GeckoViewStreamingTelemetry::RegisterDelegate(
-        new GeckoTelemetryDelegate(aProxy));
-  }
-
-  explicit GeckoTelemetryDelegate(
-      mozilla::java::RuntimeTelemetry::Proxy::Param aProxy)
-      : mProxy(aProxy) {}
-
- private:
-  void DispatchHistogram(bool aIsCategorical, const nsCString& aName,
-                         const nsTArray<uint32_t>& aSamples) {
-    if (!mozilla::jni::IsAvailable() || !mProxy || aSamples.Length() < 1) {
-      return;
-    }
-
-    // Convert aSamples to an array of int64_t. We know |samples| required
-    // capacity needs to match |aSamples.Length()|.
-    nsTArray<int64_t> samples(aSamples.Length());
-    for (size_t i = 0, l = aSamples.Length(); i < l; ++i) {
-      samples.AppendElement(static_cast<int64_t>(aSamples[i]));
-    }
-
-    // LongArray::From *copies* the elements
-    mProxy->DispatchHistogram(aIsCategorical, aName,
-                              mozilla::jni::LongArray::From(samples));
-  }
-
-  // Implement StreamingTelemetryDelegate.
-  void ReceiveHistogramSamples(const nsCString& aName,
-                               const nsTArray<uint32_t>& aSamples) override {
-    DispatchHistogram(/* isCategorical */ false, aName, aSamples);
-  }
-
-  void ReceiveCategoricalHistogramSamples(
-      const nsCString& aName, const nsTArray<uint32_t>& aSamples) override {
-    DispatchHistogram(/* isCategorical */ true, aName, aSamples);
-  }
-
-  void ReceiveBoolScalarValue(const nsCString& aName, bool aValue) override {
-    if (!mozilla::jni::IsAvailable() || !mProxy) {
-      return;
-    }
-
-    mProxy->DispatchBooleanScalar(aName, aValue);
-  }
-
-  void ReceiveStringScalarValue(const nsCString& aName,
-                                const nsCString& aValue) override {
-    if (!mozilla::jni::IsAvailable() || !mProxy) {
-      return;
-    }
-
-    mProxy->DispatchStringScalar(aName, aValue);
-  }
-
-  void ReceiveUintScalarValue(const nsCString& aName,
-                              uint32_t aValue) override {
-    if (!mozilla::jni::IsAvailable() || !mProxy) {
-      return;
-    }
-
-    mProxy->DispatchLongScalar(aName, static_cast<int64_t>(aValue));
-  }
-
-  mozilla::java::RuntimeTelemetry::Proxy::GlobalRef mProxy;
-};
-
-}  // namespace widget
-}  // namespace mozilla
-
-#endif  // GeckoTelemetryDelegate_h__
diff --git a/widget/android/jni/Utils.cpp b/widget/android/jni/Utils.cpp
index 8d3800fd03..78e1ab647a 100644
--- a/widget/android/jni/Utils.cpp
+++ b/widget/android/jni/Utils.cpp
@@ -9,6 +9,7 @@
 
 #include <android/log.h>
 #include <pthread.h>
+#include <sys/prctl.h>
 
 #include "mozilla/Assertions.h"
 #include "mozilla/java/GeckoAppShellWrappers.h"
@@ -164,10 +165,20 @@ JNIEnv* GetEnvForThread() {
     return env;
   }
 
+  // By default the VM has a nasty habit of overwriting our lovely
+  // thread names with "Thread-<n>" making them hard to identify in a debugger,
+  // so we pass the name in AttachArgs below to prevent that from happening.
+  // PR_GET_NAME requires a 16 byte buffer: https://linux.die.net/man/2/prctl.
+  // JNI_VERSION_1_4 is required for NewDirectByteBuffer.
+  char threadName[16] = {'\0'};
+  prctl(PR_GET_NAME, threadName);
+  JavaVMAttachArgs attachArgs{
+      .version = JNI_VERSION_1_4, .name = threadName, .group = nullptr};
+
   // We don't have a saved JNIEnv, so try to get one.
   // AttachCurrentThread() does the same thing as GetEnv() when a thread is
   // already attached, so we don't have to call GetEnv() at all.
-  if (!sJavaVM->AttachCurrentThread(&env, nullptr)) {
+  if (!sJavaVM->AttachCurrentThread(&env, &attachArgs)) {
     MOZ_ASSERT(env);
     MOZ_ALWAYS_TRUE(!pthread_setspecific(sThreadEnvKey, env));
     return env;
diff --git a/widget/android/moz.build b/widget/android/moz.build
index e4525bb747..2623442020 100644
--- a/widget/android/moz.build
+++ b/widget/android/moz.build
@@ -69,7 +69,6 @@ classes_with_WrapForJNI = [
     "ImageDecoder",
     "MediaDrmProxy",
     "PanZoomController",
-    "RuntimeTelemetry",
     "Sample",
     "SampleBuffer",
     "ScreenManagerHelper",
@@ -193,7 +192,6 @@ LOCAL_INCLUDES += [
     "/layout/forms",
     "/layout/painting",
     "/netwerk/base",
-    "/toolkit/components/telemetry",
     "/widget",
     "/widget/headless",
     "/xpcom/threads",
diff --git a/widget/android/nsAppShell.cpp b/widget/android/nsAppShell.cpp
index 4d396945c4..c42f025b2c 100644
--- a/widget/android/nsAppShell.cpp
+++ b/widget/android/nsAppShell.cpp
@@ -69,7 +69,6 @@
 #include "GeckoNetworkManager.h"
 #include "GeckoProcessManager.h"
 #include "GeckoSystemStateListener.h"
-#include "GeckoTelemetryDelegate.h"
 #include "GeckoVRManager.h"
 #include "ImageDecoderSupport.h"
 #include "JavaBuiltins.h"
@@ -412,7 +411,6 @@ nsAppShell::nsAppShell()
       GeckoAppShellSupport::Init();
       XPCOMEventTargetWrapper::Init();
       mozilla::widget::Telemetry::Init();
-      mozilla::widget::GeckoTelemetryDelegate::Init();
 
       if (XRE_IsGPUProcess()) {
         mozilla::gl::AndroidSurfaceTexture::Init();
@@ -443,7 +441,6 @@ nsAppShell::nsAppShell()
     mozilla::widget::Base64UtilsSupport::Init();
     nsWindow::InitNatives();
     mozilla::gl::AndroidSurfaceTexture::Init();
-    mozilla::widget::GeckoTelemetryDelegate::Init();
 
     java::GeckoThread::SetState(java::GeckoThread::State::JNI_READY());
 
diff --git a/widget/android/nsClipboard.cpp b/widget/android/nsClipboard.cpp
index c2a03dd540..3c94b89c01 100644
--- a/widget/android/nsClipboard.cpp
+++ b/widget/android/nsClipboard.cpp
@@ -164,7 +164,7 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
     }
   }
 
-  return NS_ERROR_FAILURE;
+  return NS_OK;
 }
 
 nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
diff --git a/widget/cocoa/AppearanceOverride.h b/widget/cocoa/AppearanceOverride.h
deleted file mode 100644
index c4ae629320..0000000000
--- a/widget/cocoa/AppearanceOverride.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef AppearanceOverride_h
-#define AppearanceOverride_h
-
-#import <Cocoa/Cocoa.h>
-
-// Implements support for the browser.theme.toolbar-theme pref.
-// Use MOZGlobalAppearance.sharedInstance.effectiveAppearance
-// in all places where you would like the global override to be respected. The
-// effectiveAppearance property can be key-value observed.
-@interface MOZGlobalAppearance : NSObject <NSAppearanceCustomization>
-@property(class, readonly) MOZGlobalAppearance* sharedInstance;
-@end
-
-#endif
diff --git a/widget/cocoa/AppearanceOverride.mm b/widget/cocoa/AppearanceOverride.mm
deleted file mode 100644
index c3938d6b93..0000000000
--- a/widget/cocoa/AppearanceOverride.mm
+++ /dev/null
@@ -1,90 +0,0 @@
-/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#import <Cocoa/Cocoa.h>
-
-#include "AppearanceOverride.h"
-
-#include "mozilla/Preferences.h"
-#include "mozilla/StaticPrefs_browser.h"
-#include "mozilla/StaticPrefs_widget.h"
-
-#include "nsXULAppAPI.h"
-
-static void ToolbarThemePrefChanged(const char* aPref, void* aUserInfo);
-
-@interface MOZGlobalAppearance ()
-@property NSInteger toolbarTheme;
-@end
-
-@implementation MOZGlobalAppearance
-
-+ (MOZGlobalAppearance*)sharedInstance {
-  static MOZGlobalAppearance* sInstance = nil;
-  if (!sInstance) {
-    sInstance = [[MOZGlobalAppearance alloc] init];
-    if (XRE_IsParentProcess()) {
-      mozilla::Preferences::RegisterCallbackAndCall(
-          &ToolbarThemePrefChanged,
-          nsDependentCString(
-              mozilla::StaticPrefs::GetPrefName_browser_theme_toolbar_theme()));
-    }
-  }
-  return sInstance;
-}
-
-+ (NSSet*)keyPathsForValuesAffectingAppearance {
-  return [NSSet setWithObjects:@"toolbarTheme", nil];
-}
-
-- (NSAppearance*)appearance {
-  switch (self.toolbarTheme) {  // Value for browser.theme.toolbar-theme pref
-    case 0:                     // Dark
-      return [NSAppearance appearanceNamed:NSAppearanceNameDarkAqua];
-    case 1:  // Light
-      return [NSAppearance appearanceNamed:NSAppearanceNameAqua];
-    case 2:  // System
-    default:
-      return nil;  // nil means "no override".
-  }
-}
-
-- (void)setAppearance:(NSAppearance*)aAppearance {
-  // ignored
-}
-
-- (NSApplication*)_app {
-  return NSApp;
-}
-
-+ (NSSet*)keyPathsForValuesAffectingEffectiveAppearance {
-  // Automatically notify any key-value observers of our effectiveAppearance
-  // property whenever the pref or the NSApp's effectiveAppearance change.
-  return
-      [NSSet setWithObjects:@"toolbarTheme", @"_app.effectiveAppearance", nil];
-}
-
-- (NSAppearance*)effectiveAppearance {
-  switch (self.toolbarTheme) {  // Value for browser.theme.toolbar-theme pref
-    case 0:                     // Dark
-      return [NSAppearance appearanceNamed:NSAppearanceNameDarkAqua];
-    case 1:  // Light
-      return [NSAppearance appearanceNamed:NSAppearanceNameAqua];
-    case 2:  // System
-    default:
-      // Use the NSApp effectiveAppearance. This is the system appearance.
-      return NSApp.effectiveAppearance;
-  }
-}
-
-@end
-
-static void ToolbarThemePrefChanged(const char* aPref, void* aUserInfo) {
-  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
-  MOZ_RELEASE_ASSERT(NS_IsMainThread());
-
-  MOZGlobalAppearance.sharedInstance.toolbarTheme =
-      mozilla::StaticPrefs::browser_theme_toolbar_theme();
-}
diff --git a/widget/cocoa/VibrancyManager.h b/widget/cocoa/VibrancyManager.h
index c70ec60a3b..43adace794 100644
--- a/widget/cocoa/VibrancyManager.h
+++ b/widget/cocoa/VibrancyManager.h
@@ -7,24 +7,24 @@
 #ifndef VibrancyManager_h
 #define VibrancyManager_h
 
-#include "mozilla/Assertions.h"
-#include "nsClassHashtable.h"
-#include "nsRegion.h"
-#include "nsTArray.h"
-#include "ViewRegion.h"
+#include "mozilla/EnumeratedArray.h"
+#include "Units.h"
 
-#import <Foundation/NSGeometry.h>
-
-@class NSColor;
 @class NSView;
 class nsChildView;
 
 namespace mozilla {
 
+class ViewRegion;
+
 enum class VibrancyType {
-  TOOLTIP,
-  MENU,
-  TITLEBAR,
+  // Add new values here, or update MaxEnumValue below if you add them after.
+  Titlebar,
+};
+
+template <>
+struct MaxContiguousEnumValue<VibrancyType> {
+  static constexpr auto value = VibrancyType::Titlebar;
 };
 
 /**
@@ -51,9 +51,9 @@ class VibrancyManager {
    *   NSVisualEffectViews which will be created for vibrant regions.
    */
   VibrancyManager(const nsChildView& aCoordinateConverter,
-                  NSView* aContainerView)
-      : mCoordinateConverter(aCoordinateConverter),
-        mContainerView(aContainerView) {}
+                  NSView* aContainerView);
+
+  ~VibrancyManager();
 
   /**
    * Update the placement of the NSVisualEffectViews inside the container
@@ -66,26 +66,10 @@ class VibrancyManager {
   bool UpdateVibrantRegion(VibrancyType aType,
                            const LayoutDeviceIntRegion& aRegion);
 
-  bool HasVibrantRegions() { return !mVibrantRegions.IsEmpty(); }
-
-  LayoutDeviceIntRegion GetUnionOfVibrantRegions() const;
-
-  /**
-   * Create an NSVisualEffectView for the specified vibrancy type. The return
-   * value is not autoreleased. We return an object of type NSView* because we
-   * compile with an SDK that does not contain a definition for
-   * NSVisualEffectView.
-   * @param aIsContainer Whether this NSView will have child views. This value
-   *                     affects hit testing: Container views will pass through
-   *                     hit testing requests to their children, and leaf views
-   *                     will be transparent to hit testing.
-   */
-  static NSView* CreateEffectView(VibrancyType aType, BOOL aIsContainer = NO);
-
  protected:
   const nsChildView& mCoordinateConverter;
   NSView* mContainerView;
-  nsClassHashtable<nsUint32HashKey, ViewRegion> mVibrantRegions;
+  EnumeratedArray<VibrancyType, UniquePtr<ViewRegion>> mVibrantRegions;
 };
 
 }  // namespace mozilla
diff --git a/widget/cocoa/VibrancyManager.mm b/widget/cocoa/VibrancyManager.mm
index 6062acb931..a2bef29a19 100644
--- a/widget/cocoa/VibrancyManager.mm
+++ b/widget/cocoa/VibrancyManager.mm
@@ -5,6 +5,9 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "VibrancyManager.h"
+#include "ViewRegion.h"
+#include "nsRegion.h"
+#include "ViewRegion.h"
 
 #import <objc/message.h>
 
@@ -20,18 +23,10 @@ using namespace mozilla;
                  vibrancyType:(VibrancyType)aVibrancyType;
 @end
 
-@interface MOZVibrantLeafView : MOZVibrantView
-@end
-
 static NSVisualEffectState VisualEffectStateForVibrancyType(
     VibrancyType aType) {
   switch (aType) {
-    case VibrancyType::TOOLTIP:
-    case VibrancyType::MENU:
-      // Tooltip and menu windows are never "key", so we need to tell the
-      // vibrancy effect to look active regardless of window state.
-      return NSVisualEffectStateActive;
-    case VibrancyType::TITLEBAR:
+    case VibrancyType::Titlebar:
       break;
   }
   return NSVisualEffectStateFollowsWindowActiveState;
@@ -40,11 +35,7 @@ static NSVisualEffectState VisualEffectStateForVibrancyType(
 static NSVisualEffectMaterial VisualEffectMaterialForVibrancyType(
     VibrancyType aType) {
   switch (aType) {
-    case VibrancyType::TOOLTIP:
-      return (NSVisualEffectMaterial)NSVisualEffectMaterialToolTip;
-    case VibrancyType::MENU:
-      return NSVisualEffectMaterialMenu;
-    case VibrancyType::TITLEBAR:
+    case VibrancyType::Titlebar:
       return NSVisualEffectMaterialTitlebar;
   }
 }
@@ -52,10 +43,7 @@ static NSVisualEffectMaterial VisualEffectMaterialForVibrancyType(
 static NSVisualEffectBlendingMode VisualEffectBlendingModeForVibrancyType(
     VibrancyType aType) {
   switch (aType) {
-    case VibrancyType::TOOLTIP:
-    case VibrancyType::MENU:
-      return NSVisualEffectBlendingModeBehindWindow;
-    case VibrancyType::TITLEBAR:
+    case VibrancyType::Titlebar:
       return StaticPrefs::widget_macos_titlebar_blend_mode_behind_window()
                  ? NSVisualEffectBlendingModeBehindWindow
                  : NSVisualEffectBlendingModeWithinWindow;
@@ -63,7 +51,6 @@ static NSVisualEffectBlendingMode VisualEffectBlendingModeForVibrancyType(
 }
 
 @implementation MOZVibrantView
-
 - (instancetype)initWithFrame:(NSRect)aRect vibrancyType:(VibrancyType)aType {
   self = [super initWithFrame:aRect];
   mType = aType;
@@ -76,50 +63,31 @@ static NSVisualEffectBlendingMode VisualEffectBlendingModeForVibrancyType(
   return self;
 }
 
-// Don't override allowsVibrancy here, because this view may have subviews, and
-// returning YES from allowsVibrancy forces on foreground vibrancy for all
-// descendant views, which can have unintended effects.
-
-@end
-
-@implementation MOZVibrantLeafView
-
 - (NSView*)hitTest:(NSPoint)aPoint {
   // This view must be transparent to mouse events.
   return nil;
 }
+@end
 
-// MOZVibrantLeafView does not have subviews, so we can return YES here without
-// having unintended effects on other contents of the window.
-- (BOOL)allowsVibrancy {
-  return NO;
-}
+VibrancyManager::VibrancyManager(const nsChildView& aCoordinateConverter,
+                                 NSView* aContainerView)
+    : mCoordinateConverter(aCoordinateConverter),
+      mContainerView(aContainerView) {}
 
-@end
+VibrancyManager::~VibrancyManager() = default;
 
 bool VibrancyManager::UpdateVibrantRegion(
     VibrancyType aType, const LayoutDeviceIntRegion& aRegion) {
+  auto& slot = mVibrantRegions[aType];
   if (aRegion.IsEmpty()) {
-    return mVibrantRegions.Remove(uint32_t(aType));
+    bool hadRegion = !!slot;
+    slot = nullptr;
+    return hadRegion;
   }
-  auto& vr = *mVibrantRegions.GetOrInsertNew(uint32_t(aType));
-  return vr.UpdateRegion(aRegion, mCoordinateConverter, mContainerView, ^() {
-    return CreateEffectView(aType);
-  });
-}
-
-LayoutDeviceIntRegion VibrancyManager::GetUnionOfVibrantRegions() const {
-  LayoutDeviceIntRegion result;
-  for (const auto& region : mVibrantRegions.Values()) {
-    result.OrWith(region->Region());
+  if (!slot) {
+    slot = MakeUnique<ViewRegion>();
   }
-  return result;
-}
-
-/* static */ NSView* VibrancyManager::CreateEffectView(VibrancyType aType,
-                                                       BOOL aIsContainer) {
-  return aIsContainer ? [[MOZVibrantView alloc] initWithFrame:NSZeroRect
-                                                 vibrancyType:aType]
-                      : [[MOZVibrantLeafView alloc] initWithFrame:NSZeroRect
-                                                     vibrancyType:aType];
+  return slot->UpdateRegion(aRegion, mCoordinateConverter, mContainerView, ^() {
+    return [[MOZVibrantView alloc] initWithFrame:NSZeroRect vibrancyType:aType];
+  });
 }
diff --git a/widget/cocoa/ViewRegion.h b/widget/cocoa/ViewRegion.h
index b2ed0c8835..d44bde5f71 100644
--- a/widget/cocoa/ViewRegion.h
+++ b/widget/cocoa/ViewRegion.h
@@ -8,6 +8,7 @@
 #define ViewRegion_h
 
 #include "Units.h"
+#include "nsRegion.h"
 #include "nsTArray.h"
 
 class nsChildView;
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
index d0939d34c7..125a7f2fc0 100644
--- a/widget/cocoa/moz.build
+++ b/widget/cocoa/moz.build
@@ -23,7 +23,6 @@ EXPORTS += [
 ]
 
 UNIFIED_SOURCES += [
-    "AppearanceOverride.mm",
     "GfxInfo.mm",
     "MOZIconHelper.mm",
     "MOZMenuOpeningCoordinator.mm",
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index d3241a983f..b57df15825 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -1726,32 +1726,52 @@ static Maybe<VibrancyType> ThemeGeometryTypeToVibrancyType(
     nsITheme::ThemeGeometryType aThemeGeometryType) {
   switch (aThemeGeometryType) {
     case eThemeGeometryTypeTitlebar:
-      return Some(VibrancyType::TITLEBAR);
+      return Some(VibrancyType::Titlebar);
     default:
       return Nothing();
   }
 }
 
-static LayoutDeviceIntRegion GatherVibrantRegion(
-    const nsTArray<nsIWidget::ThemeGeometry>& aThemeGeometries,
-    VibrancyType aVibrancyType) {
-  LayoutDeviceIntRegion region;
+static EnumeratedArray<VibrancyType, LayoutDeviceIntRegion>
+GatherVibrantRegions(Span<const nsIWidget::ThemeGeometry> aThemeGeometries) {
+  EnumeratedArray<VibrancyType, LayoutDeviceIntRegion> regions;
   for (const auto& geometry : aThemeGeometries) {
-    if (ThemeGeometryTypeToVibrancyType(geometry.mType) ==
-        Some(aVibrancyType)) {
-      region.OrWith(geometry.mRect);
+    auto vibrancyType = ThemeGeometryTypeToVibrancyType(geometry.mType);
+    if (!vibrancyType) {
+      continue;
     }
+    regions[*vibrancyType].OrWith(geometry.mRect);
+  }
+  return regions;
+}
+
+// Subtracts parts from regions in such a way that they don't have any overlap.
+// Each region in the argument list will have the union of all the regions
+// *following* it subtracted from itself. In other words, the arguments are
+// treated as low priority to high priority.
+static void MakeRegionsNonOverlapping(Span<LayoutDeviceIntRegion> aRegions) {
+  LayoutDeviceIntRegion unionOfAll;
+  for (auto& region : aRegions) {
+    region.SubOut(unionOfAll);
+    unionOfAll.OrWith(region);
   }
-  return region;
 }
 
 void nsChildView::UpdateVibrancy(
     const nsTArray<ThemeGeometry>& aThemeGeometries) {
-  LayoutDeviceIntRegion titlebarRegion =
-      GatherVibrantRegion(aThemeGeometries, VibrancyType::TITLEBAR);
+  auto regions = GatherVibrantRegions(aThemeGeometries);
+  MakeRegionsNonOverlapping(regions);
 
   auto& vm = EnsureVibrancyManager();
-  bool changed = vm.UpdateVibrantRegion(VibrancyType::TITLEBAR, titlebarRegion);
+  bool changed = false;
+
+  // EnumeratedArray doesn't have an iterator that also yields the enum type,
+  // but we rely on VibrancyType being contiguous and starting at 0, so we can
+  // do that manually.
+  size_t i = 0;
+  for (const auto& region : regions) {
+    changed |= vm.UpdateVibrantRegion(VibrancyType(i++), region);
+  }
 
   if (changed) {
     SuspendAsyncCATransactions();
diff --git a/widget/cocoa/nsClipboard.mm b/widget/cocoa/nsClipboard.mm
index ba747e5b27..1c4788460c 100644
--- a/widget/cocoa/nsClipboard.mm
+++ b/widget/cocoa/nsClipboard.mm
@@ -499,13 +499,12 @@ nsClipboard::HasNativeClipboardDataMatchingFlavors(
         // XXX we only check the first pasteboard item as we only get data from
         // first item in TransferableFromPasteboard for now.
         if (NSPasteboardItem* item = [items objectAtIndex:0]) {
-          if (NSString *availableType = [item
-                  availableTypeFromArray:
-                      [NSArray
-                          arrayWithObjects:[UTIHelper
-                                               stringFromPboardType:
-                                                   (NSString*)kUTTypeFileURL],
-                                           nil]]) {
+          if ([item availableTypeFromArray:
+                        [NSArray
+                            arrayWithObjects:[UTIHelper
+                                                 stringFromPboardType:
+                                                     (NSString*)kUTTypeFileURL],
+                                             nil]]) {
             MOZ_CLIPBOARD_LOG("    has %s\n", mimeType.get());
             return true;
           }
diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
index 8e54d9e7fd..5032f35fa1 100644
--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -6,7 +6,6 @@
 
 #include "nsCocoaWindow.h"
 
-#include "AppearanceOverride.h"
 #include "NativeKeyBindings.h"
 #include "ScreenHelperCocoa.h"
 #include "TextInputHandler.h"
@@ -158,6 +157,13 @@ void nsCocoaWindow::DestroyNativeWindow() {
   // we clear our delegate.
   EndOurNativeTransition();
 
+  // We are about to destroy mWindow. Before we do that, make sure that we
+  // hide the window using the Show() method, because it has several side
+  // effects that our parent and listeners might be expecting. If we don't
+  // do this now, then these side effects will never execute, though the
+  // window will definitely no longer be shown.
+  Show(false);
+
   [mWindow releaseJSObjects];
   // We want to unhook the delegate here because we don't want events
   // sent to it after this object has been destroyed.
@@ -525,10 +531,6 @@ nsresult nsCocoaWindow::CreateNativeWindow(const NSRect& aRect,
   [WindowDataMap.sharedWindowDataMap ensureDataForWindow:mWindow];
   mWindowMadeHere = true;
 
-  // Make the window respect the global appearance, which follows the
-  // browser.theme.toolbar-theme pref.
-  mWindow.appearanceSource = MOZGlobalAppearance.sharedInstance;
-
   return NS_OK;
 
   NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
@@ -1969,7 +1971,6 @@ void nsCocoaWindow::BackingScaleFactorChanged() {
   if (PresShell* presShell = mWidgetListener->GetPresShell()) {
     presShell->BackingScaleFactorChanged();
   }
-  mWidgetListener->UIResolutionChanged();
 }
 
 int32_t nsCocoaWindow::RoundsWidgetCoordinatesTo() {
@@ -2327,9 +2328,11 @@ void nsCocoaWindow::SetColorScheme(const Maybe<ColorScheme>& aScheme) {
   if (!mWindow) {
     return;
   }
-
-  mWindow.appearance = aScheme ? NSAppearanceForColorScheme(*aScheme) : nil;
-
+  NSAppearance* appearance =
+      aScheme ? NSAppearanceForColorScheme(*aScheme) : nil;
+  if (mWindow.appearance != appearance) {
+    mWindow.appearance = appearance;
+  }
   NS_OBJC_END_TRY_IGNORE_BLOCK;
 }
 
@@ -3071,10 +3074,6 @@ static NSMutableSet* gSwizzledFrameViewClasses = nil;
 - (void)_setNeedsDisplayInRect:(NSRect)aRect;
 @end
 
-@interface NSView (NSVisualEffectViewSetMaskImage)
-- (void)setMaskImage:(NSImage*)image;
-@end
-
 @interface BaseWindow (Private)
 - (void)removeTrackingArea;
 - (void)cursorUpdated:(NSEvent*)aEvent;
@@ -3174,35 +3173,38 @@ static NSImage* GetMenuMaskImage() {
   return maskImage;
 }
 
-- (void)swapOutChildViewWrapper:(NSView*)aNewWrapper {
-  aNewWrapper.frame = self.contentView.frame;
+// Add an effect view wrapper if needed so that the OS draws the appropriate
+// vibrancy effect and window border.
+- (void)setEffectViewWrapperForStyle:(WindowShadow)aStyle {
+  NSView* wrapper = [&]() -> NSView* {
+    if (aStyle == WindowShadow::Menu || aStyle == WindowShadow::Tooltip) {
+      const bool isMenu = aStyle == WindowShadow::Menu;
+      auto* effectView =
+          [[NSVisualEffectView alloc] initWithFrame:self.contentView.frame];
+      effectView.material =
+          isMenu ? NSVisualEffectMaterialMenu : NSVisualEffectMaterialToolTip;
+      // Tooltip and menu windows are never "key", so we need to tell the
+      // vibrancy effect to look active regardless of window state.
+      effectView.state = NSVisualEffectStateActive;
+      effectView.blendingMode = NSVisualEffectBlendingModeBehindWindow;
+      if (isMenu) {
+        // Turn on rounded corner masking.
+        effectView.maskImage = GetMenuMaskImage();
+      }
+      return effectView;
+    }
+    return [[NSView alloc] initWithFrame:self.contentView.frame];
+  }();
+
+  wrapper.wantsLayer = YES;
+  // Swap out our content view by the new view. Setting .contentView releases
+  // the old view.
   NSView* childView = [self.mainChildView retain];
   [childView removeFromSuperview];
-  [aNewWrapper addSubview:childView];
+  [wrapper addSubview:childView];
   [childView release];
-  [super setContentView:aNewWrapper];
-}
-
-- (void)setEffectViewWrapperForStyle:(WindowShadow)aStyle {
-  if (aStyle == WindowShadow::Menu || aStyle == WindowShadow::Tooltip) {
-    // Add an effect view wrapper so that the OS draws the appropriate
-    // vibrancy effect and window border.
-    BOOL isMenu = aStyle == WindowShadow::Menu;
-    NSView* effectView = VibrancyManager::CreateEffectView(
-        isMenu ? VibrancyType::MENU : VibrancyType::TOOLTIP, YES);
-    if (isMenu) {
-      // Turn on rounded corner masking.
-      [effectView setMaskImage:GetMenuMaskImage()];
-    }
-    [self swapOutChildViewWrapper:effectView];
-    [effectView release];
-  } else {
-    // Remove the existing wrapper.
-    NSView* wrapper = [[NSView alloc] initWithFrame:NSZeroRect];
-    [wrapper setWantsLayer:YES];
-    [self swapOutChildViewWrapper:wrapper];
-    [wrapper release];
-  }
+  super.contentView = wrapper;
+  [wrapper release];
 }
 
 - (NSTouchBar*)makeTouchBar {
diff --git a/widget/cocoa/nsLookAndFeel.mm b/widget/cocoa/nsLookAndFeel.mm
index 779984be0c..69bd348da8 100644
--- a/widget/cocoa/nsLookAndFeel.mm
+++ b/widget/cocoa/nsLookAndFeel.mm
@@ -3,7 +3,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "AppearanceOverride.h"
 #include "mozilla/widget/ThemeChangeKind.h"
 #include "nsLookAndFeel.h"
 #include "nsCocoaFeatures.h"
@@ -239,9 +238,6 @@ nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
     case ColorID::MozButtonhoverface:
     case ColorID::MozButtonactiveface:
     case ColorID::MozButtondisabledface:
-    case ColorID::MozColheader:
-    case ColorID::MozColheaderhover:
-    case ColorID::MozColheaderactive:
       color = GetColorFromNSColor(NSColor.controlColor);
       if (!NS_GET_A(color)) {
         color = GetColorFromNSColor(NSColor.controlBackgroundColor);
@@ -301,9 +297,6 @@ nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
     case ColorID::Menutext:
     case ColorID::Infotext:
     case ColorID::MozCellhighlighttext:
-    case ColorID::MozColheadertext:
-    case ColorID::MozColheaderhovertext:
-    case ColorID::MozColheaderactivetext:
     case ColorID::MozSidebartext:
       color = GetColorFromNSColor(NSColor.controlTextColor);
       break;
@@ -319,6 +312,17 @@ nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
       // For inactive list selection
       color = GetColorFromNSColor(NSColor.secondarySelectedControlColor);
       break;
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+    case ColorID::MozColheaderactivetext:
+      color = GetColorFromNSColor(NSColor.headerTextColor);
+      break;
+    case ColorID::MozColheaderactive:
+      color = GetColorFromNSColor(
+          NSColor.unemphasizedSelectedContentBackgroundColor);
+      break;
+    case ColorID::MozColheader:
+    case ColorID::MozColheaderhover:
     case ColorID::MozEventreerow:
       // Background color of even list rows.
       color =
@@ -460,11 +464,6 @@ nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
     case IntID::AlertNotificationOrigin:
       aResult = NS_ALERT_TOP;
       break;
-    case IntID::TabFocusModel:
-      aResult = [NSApp isFullKeyboardAccessEnabled]
-                    ? nsIContent::eTabFocus_any
-                    : nsIContent::eTabFocus_textControlsMask;
-      break;
     case IntID::ScrollToClick: {
       aResult = [[NSUserDefaults standardUserDefaults]
           boolForKey:@"AppleScrollerPagingBehavior"];
@@ -630,10 +629,6 @@ void nsLookAndFeel::RecordAccessibilityTelemetry() {
                   object:nil
       suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];
 
-  [MOZGlobalAppearance.sharedInstance addObserver:self
-                                       forKeyPath:@"effectiveAppearance"
-                                          options:0
-                                          context:nil];
   [NSApp addObserver:self
           forKeyPath:@"effectiveAppearance"
              options:0
diff --git a/widget/cocoa/nsNativeThemeCocoa.h b/widget/cocoa/nsNativeThemeCocoa.h
index ebbf782264..66e5aec1df 100644
--- a/widget/cocoa/nsNativeThemeCocoa.h
+++ b/widget/cocoa/nsNativeThemeCocoa.h
@@ -40,8 +40,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
     eSquareBezelPushButton,
     eArrowButton,
     eHelpButton,
-    eTreeTwistyPointingRight,
-    eTreeTwistyPointingDown,
     eDisclosureButtonClosed,
     eDisclosureButtonOpen
   };
@@ -131,12 +129,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
     bool rtl = false;
   };
 
-  struct TreeHeaderCellParams {
-    ControlParams controlParams;
-    TreeSortDirection sortDirection = eTreeSortDirection_Natural;
-    bool lastTreeHeaderCell = false;
-  };
-
   struct ScaleParams {
     int32_t value = 0;
     int32_t min = 0;
@@ -165,7 +157,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
     eSearchField,         // TextFieldParams
     eProgressBar,         // ProgressParams
     eMeter,               // MeterParams
-    eTreeHeaderCell,      // TreeHeaderCellParams
     eScale,               // ScaleParams
     eMultilineTextField,  // bool
     eListBox,
@@ -221,9 +212,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
     static WidgetInfo Meter(const MeterParams& aParams) {
       return WidgetInfo(Widget::eMeter, aParams);
     }
-    static WidgetInfo TreeHeaderCell(const TreeHeaderCellParams& aParams) {
-      return WidgetInfo(Widget::eTreeHeaderCell, aParams);
-    }
     static WidgetInfo Scale(const ScaleParams& aParams) {
       return WidgetInfo(Widget::eScale, aParams);
     }
@@ -251,7 +239,7 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
     mozilla::Variant<mozilla::gfx::sRGBColor, CheckboxOrRadioParams,
                      ButtonParams, DropdownParams, SpinButtonParams,
                      SegmentParams, TextFieldParams, ProgressParams,
-                     MeterParams, TreeHeaderCellParams, ScaleParams, bool>
+                     MeterParams, ScaleParams, bool>
         mVariant;
 
     enum Widget mWidget;
@@ -262,47 +250,42 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
   NS_DECL_ISUPPORTS_INHERITED
 
   // The nsITheme interface.
-  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
-                                  StyleAppearance aAppearance,
-                                  const nsRect& aRect, const nsRect& aDirtyRect,
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame*,
+                                  StyleAppearance, const nsRect& aRect,
+                                  const nsRect& aDirtyRect,
                                   DrawOverflow) override;
   bool CreateWebRenderCommandsForWidget(
       mozilla::wr::DisplayListBuilder& aBuilder,
       mozilla::wr::IpcResourceUpdateQueue& aResources,
       const mozilla::layers::StackingContextHelper& aSc,
-      mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
-      StyleAppearance aAppearance, const nsRect& aRect) override;
-  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(
-      nsDeviceContext* aContext, nsIFrame* aFrame,
-      StyleAppearance aAppearance) override;
-
-  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
-                        StyleAppearance aAppearance,
+      mozilla::layers::RenderRootStateManager* aManager, nsIFrame*,
+      StyleAppearance, const nsRect& aRect) override;
+  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(nsDeviceContext* aContext,
+                                                      nsIFrame*,
+                                                      StyleAppearance) override;
+
+  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame*, StyleAppearance,
                         LayoutDeviceIntMargin* aResult) override;
 
-  virtual bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
-                                 StyleAppearance aAppearance,
-                                 nsRect* aOverflowRect) override;
+  bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame*, StyleAppearance,
+                         nsRect* aOverflowRect) override;
 
   LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*, nsIFrame*,
                                            StyleAppearance) override;
-  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aAppearance,
-                                nsAtom* aAttribute, bool* aShouldRepaint,
+  NS_IMETHOD WidgetStateChanged(nsIFrame*, StyleAppearance, nsAtom* aAttribute,
+                                bool* aShouldRepaint,
                                 const nsAttrValue* aOldValue) override;
   NS_IMETHOD ThemeChanged() override;
-  bool ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
-                           StyleAppearance aAppearance) override;
-  bool WidgetIsContainer(StyleAppearance aAppearance) override;
+  bool ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame*,
+                           StyleAppearance) override;
+  bool WidgetIsContainer(StyleAppearance) override;
   bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) override;
   bool ThemeNeedsComboboxDropmarker() override;
-  virtual bool WidgetAppearanceDependsOnWindowFocus(
-      StyleAppearance aAppearance) override;
-  virtual ThemeGeometryType ThemeGeometryTypeForWidget(
-      nsIFrame* aFrame, StyleAppearance aAppearance) override;
-  virtual Transparency GetWidgetTransparency(
-      nsIFrame* aFrame, StyleAppearance aAppearance) override;
-  mozilla::Maybe<WidgetInfo> ComputeWidgetInfo(nsIFrame* aFrame,
-                                               StyleAppearance aAppearance,
+  bool WidgetAppearanceDependsOnWindowFocus(StyleAppearance) override;
+  ThemeGeometryType ThemeGeometryTypeForWidget(nsIFrame*,
+                                               StyleAppearance) override;
+  Transparency GetWidgetTransparency(nsIFrame*, StyleAppearance) override;
+  mozilla::Maybe<WidgetInfo> ComputeWidgetInfo(nsIFrame*, StyleAppearance,
                                                const nsRect& aRect);
   void DrawProgress(CGContextRef context, const HIRect& inBoxRect,
                     const ProgressParams& aParams);
@@ -310,24 +293,18 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
  protected:
   virtual ~nsNativeThemeCocoa();
 
-  LayoutDeviceIntMargin DirectionAwareMargin(
-      const LayoutDeviceIntMargin& aMargin, nsIFrame* aFrame);
+  LayoutDeviceIntMargin DirectionAwareMargin(const LayoutDeviceIntMargin&,
+                                             nsIFrame*);
   nsIFrame* SeparatorResponsibility(nsIFrame* aBefore, nsIFrame* aAfter);
-  ControlParams ComputeControlParams(nsIFrame* aFrame,
-                                     mozilla::dom::ElementState aEventState);
-  SegmentParams ComputeSegmentParams(nsIFrame* aFrame,
-                                     mozilla::dom::ElementState aEventState,
-                                     SegmentType aSegmentType);
-  TextFieldParams ComputeTextFieldParams(
-      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
-  ProgressParams ComputeProgressParams(nsIFrame* aFrame,
-                                       mozilla::dom::ElementState aEventState,
+  ControlParams ComputeControlParams(nsIFrame*, mozilla::dom::ElementState);
+  SegmentParams ComputeSegmentParams(nsIFrame*, mozilla::dom::ElementState,
+                                     SegmentType);
+  TextFieldParams ComputeTextFieldParams(nsIFrame*, mozilla::dom::ElementState);
+  ProgressParams ComputeProgressParams(nsIFrame*, mozilla::dom::ElementState,
                                        bool aIsHorizontal);
-  MeterParams ComputeMeterParams(nsIFrame* aFrame);
-  TreeHeaderCellParams ComputeTreeHeaderCellParams(
-      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
+  MeterParams ComputeMeterParams(nsIFrame*);
   mozilla::Maybe<ScaleParams> ComputeHTMLScaleParams(
-      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
+      nsIFrame*, mozilla::dom::ElementState);
 
   // HITheme drawing routines
   void DrawMeter(CGContextRef context, const HIRect& inBoxRect,
@@ -363,8 +340,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
                          const ControlParams& aParams);
   void DrawButton(CGContextRef context, const HIRect& inBoxRect,
                   const ButtonParams& aParams);
-  void DrawTreeHeaderCell(CGContextRef context, const HIRect& inBoxRect,
-                          const TreeHeaderCellParams& aParams);
   void DrawDropdown(CGContextRef context, const HIRect& inBoxRect,
                     const DropdownParams& aParams);
   HIThemeButtonDrawInfo SpinButtonDrawInfo(ThemeButtonKind aKind,
@@ -396,7 +371,6 @@ class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
   NSComboBoxCell* mComboBoxCell;
   NSProgressBarCell* mProgressBarCell;
   NSLevelIndicatorCell* mMeterBarCell;
-  NSTableHeaderCell* mTreeHeaderCell;
   MOZCellDrawWindow* mCellDrawWindow = nil;
   MOZCellDrawView* mCellDrawView;
 };
diff --git a/widget/cocoa/nsNativeThemeCocoa.mm b/widget/cocoa/nsNativeThemeCocoa.mm
index 18913facea..ad16fac04a 100644
--- a/widget/cocoa/nsNativeThemeCocoa.mm
+++ b/widget/cocoa/nsNativeThemeCocoa.mm
@@ -458,8 +458,6 @@ nsNativeThemeCocoa::nsNativeThemeCocoa() : ThemeCocoa(ScrollbarStyle()) {
   mMeterBarCell = [[NSLevelIndicatorCell alloc]
       initWithLevelIndicatorStyle:NSLevelIndicatorStyleContinuousCapacity];
 
-  mTreeHeaderCell = [[NSTableHeaderCell alloc] init];
-
   mCellDrawView = [[MOZCellDrawView alloc] init];
 
   if (XRE_IsParentProcess()) {
@@ -498,7 +496,6 @@ nsNativeThemeCocoa::~nsNativeThemeCocoa() {
   [mSearchFieldCell release];
   [mDropdownCell release];
   [mComboBoxCell release];
-  [mTreeHeaderCell release];
   [mCellDrawWindow release];
   [mCellDrawView release];
 
@@ -1094,6 +1091,7 @@ static bool ShouldUnconditionallyDrawFocusRingIfFocused(nsIFrame* aFrame) {
   // Mac always draws focus rings for textboxes and lists.
   switch (aFrame->StyleDisplay()->EffectiveAppearance()) {
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Searchfield:
@@ -1316,17 +1314,6 @@ static void RenderButton(CGContextRef cgContext, const HIRect& aRenderRect,
                     NULL);
 }
 
-static ThemeDrawState ToThemeDrawState(
-    const nsNativeThemeCocoa::ControlParams& aParams) {
-  if (aParams.disabled) {
-    return kThemeStateUnavailable;
-  }
-  if (aParams.pressed) {
-    return kThemeStatePressed;
-  }
-  return kThemeStateActive;
-}
-
 void nsNativeThemeCocoa::DrawHIThemeButton(
     CGContextRef cgContext, const HIRect& aRect, ThemeButtonKind aKind,
     ThemeButtonValue aValue, ThemeDrawState aState,
@@ -1376,16 +1363,6 @@ void nsNativeThemeCocoa::DrawButton(CGContextRef cgContext,
     case ButtonType::eHelpButton:
       DrawHelpButton(cgContext, inBoxRect, controlParams);
       return;
-    case ButtonType::eTreeTwistyPointingRight:
-      DrawHIThemeButton(cgContext, inBoxRect, kThemeDisclosureButton,
-                        kThemeDisclosureRight, ToThemeDrawState(controlParams),
-                        kThemeAdornmentNone, controlParams);
-      return;
-    case ButtonType::eTreeTwistyPointingDown:
-      DrawHIThemeButton(cgContext, inBoxRect, kThemeDisclosureButton,
-                        kThemeDisclosureDown, ToThemeDrawState(controlParams),
-                        kThemeAdornmentNone, controlParams);
-      return;
     case ButtonType::eDisclosureButtonClosed:
       DrawDisclosureButton(cgContext, inBoxRect, controlParams,
                            NSControlStateValueOff);
@@ -1397,87 +1374,6 @@ void nsNativeThemeCocoa::DrawButton(CGContextRef cgContext,
   }
 }
 
-nsNativeThemeCocoa::TreeHeaderCellParams
-nsNativeThemeCocoa::ComputeTreeHeaderCellParams(nsIFrame* aFrame,
-                                                ElementState aEventState) {
-  TreeHeaderCellParams params;
-  params.controlParams = ComputeControlParams(aFrame, aEventState);
-  params.sortDirection = GetTreeSortDirection(aFrame);
-  params.lastTreeHeaderCell = IsLastTreeHeaderCell(aFrame);
-  return params;
-}
-
-@interface NSTableHeaderCell (NSTableHeaderCell_setSortable)
-// This method has been present in the same form since at least macOS 10.4.
-- (void)_setSortable:(BOOL)arg1
-    showSortIndicator:(BOOL)arg2
-            ascending:(BOOL)arg3
-             priority:(NSInteger)arg4
-     highlightForSort:(BOOL)arg5;
-@end
-
-void nsNativeThemeCocoa::DrawTreeHeaderCell(
-    CGContextRef cgContext, const HIRect& inBoxRect,
-    const TreeHeaderCellParams& aParams) {
-  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
-
-  // Without clearing the cell's title, it takes on a default value of "Field",
-  // which is displayed underneath the title set in the front-end.
-  NSCell* cell = (NSCell*)mTreeHeaderCell;
-  cell.title = @"";
-
-  if ([mTreeHeaderCell
-          respondsToSelector:@selector
-          (_setSortable:
-              showSortIndicator:ascending:priority:highlightForSort:)]) {
-    switch (aParams.sortDirection) {
-      case eTreeSortDirection_Ascending:
-        [mTreeHeaderCell _setSortable:YES
-                    showSortIndicator:YES
-                            ascending:YES
-                             priority:0
-                     highlightForSort:YES];
-        break;
-      case eTreeSortDirection_Descending:
-        [mTreeHeaderCell _setSortable:YES
-                    showSortIndicator:YES
-                            ascending:NO
-                             priority:0
-                     highlightForSort:YES];
-        break;
-      default:
-        // eTreeSortDirection_Natural
-        [mTreeHeaderCell _setSortable:YES
-                    showSortIndicator:NO
-                            ascending:YES
-                             priority:0
-                     highlightForSort:NO];
-        break;
-    }
-  }
-
-  mTreeHeaderCell.enabled = !aParams.controlParams.disabled;
-  mTreeHeaderCell.state =
-      (mTreeHeaderCell.enabled && aParams.controlParams.pressed)
-          ? NSControlStateValueOn
-          : NSControlStateValueOff;
-
-  mCellDrawView._drawingEndSeparator = !aParams.lastTreeHeaderCell;
-
-  NSGraphicsContext* savedContext = NSGraphicsContext.currentContext;
-  NSGraphicsContext.currentContext =
-      [NSGraphicsContext graphicsContextWithCGContext:cgContext flipped:YES];
-  DrawCellIncludingFocusRing(mTreeHeaderCell, inBoxRect, mCellDrawView);
-  NSGraphicsContext.currentContext = savedContext;
-
-#if DRAW_IN_FRAME_DEBUG
-  CGContextSetRGBFillColor(cgContext, 0.0, 0.0, 0.5, 0.25);
-  CGContextFillRect(cgContext, inBoxRect);
-#endif
-
-  NS_OBJC_END_TRY_IGNORE_BLOCK;
-}
-
 static const CellRenderSettings dropdownSettings = {
     {
         NSMakeSize(0, 16),  // mini
@@ -2159,8 +2055,6 @@ Maybe<nsNativeThemeCocoa::WidgetInfo> nsNativeThemeCocoa::ComputeWidgetInfo(
 
   switch (aAppearance) {
     case StyleAppearance::Menupopup:
-      return Nothing();
-
     case StyleAppearance::Tooltip:
       return Nothing();
 
@@ -2323,6 +2217,7 @@ Maybe<nsNativeThemeCocoa::WidgetInfo> nsNativeThemeCocoa::ComputeWidgetInfo(
 
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
       return Some(
           WidgetInfo::TextField(ComputeTextFieldParams(aFrame, elementState)));
 
@@ -2348,30 +2243,6 @@ Maybe<nsNativeThemeCocoa::WidgetInfo> nsNativeThemeCocoa::ComputeWidgetInfo(
       // Do nothing: progress and meter bars cases will draw chunks.
       break;
 
-    case StyleAppearance::Treetwisty:
-      return Some(WidgetInfo::Button(
-          ButtonParams{ComputeControlParams(aFrame, elementState),
-                       ButtonType::eTreeTwistyPointingRight}));
-
-    case StyleAppearance::Treetwistyopen:
-      return Some(WidgetInfo::Button(
-          ButtonParams{ComputeControlParams(aFrame, elementState),
-                       ButtonType::eTreeTwistyPointingDown}));
-
-    case StyleAppearance::Treeheadercell:
-      return Some(WidgetInfo::TreeHeaderCell(
-          ComputeTreeHeaderCellParams(aFrame, elementState)));
-
-    case StyleAppearance::Treeitem:
-    case StyleAppearance::Treeview:
-      return Some(WidgetInfo::ColorFill(sRGBColor(1.0, 1.0, 1.0, 1.0)));
-
-    case StyleAppearance::Treeheader:
-      // do nothing, taken care of by individual header cells
-    case StyleAppearance::Treeline:
-      // do nothing, these lines don't exist on macos
-      break;
-
     case StyleAppearance::Range: {
       Maybe<ScaleParams> params = ComputeHTMLScaleParams(aFrame, elementState);
       if (params) {
@@ -2581,12 +2452,6 @@ void nsNativeThemeCocoa::RenderWidget(const WidgetInfo& aWidgetInfo,
           DrawMeter(cgContext, macRect, params);
           break;
         }
-        case Widget::eTreeHeaderCell: {
-          TreeHeaderCellParams params =
-              aWidgetInfo.Params<TreeHeaderCellParams>();
-          DrawTreeHeaderCell(cgContext, macRect, params);
-          break;
-        }
         case Widget::eScale: {
           ScaleParams params = aWidgetInfo.Params<ScaleParams>();
           DrawScale(cgContext, macRect, params);
@@ -2668,14 +2533,10 @@ bool nsNativeThemeCocoa::CreateWebRenderCommandsForWidget(
     case StyleAppearance::MozMenulistArrowButton:
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Searchfield:
     case StyleAppearance::ProgressBar:
     case StyleAppearance::Meter:
-    case StyleAppearance::Treeheadercell:
-    case StyleAppearance::Treetwisty:
-    case StyleAppearance::Treetwistyopen:
-    case StyleAppearance::Treeitem:
-    case StyleAppearance::Treeview:
     case StyleAppearance::Range:
       return false;
 
@@ -2747,6 +2608,7 @@ LayoutDeviceIntMargin nsNativeThemeCocoa::GetWidgetBorder(
       break;
 
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield: {
       SInt32 frameOutset = 0;
       ::GetThemeMetric(kThemeMetricEditTextFrameOutset, &frameOutset);
@@ -2845,6 +2707,7 @@ bool nsNativeThemeCocoa::GetWidgetOverflow(nsDeviceContext* aContext,
     case StyleAppearance::MozMacHelpButton:
     case StyleAppearance::Toolbarbutton:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Searchfield:
@@ -2957,6 +2820,7 @@ LayoutDeviceIntSize nsNativeThemeCocoa::GetMinimumWidgetSize(
     }
 
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Searchfield: {
@@ -2985,23 +2849,6 @@ LayoutDeviceIntSize nsNativeThemeCocoa::GetMinimumWidgetSize(
       break;
     }
 
-    case StyleAppearance::Treetwisty:
-    case StyleAppearance::Treetwistyopen: {
-      SInt32 twistyHeight = 0, twistyWidth = 0;
-      ::GetThemeMetric(kThemeMetricDisclosureButtonWidth, &twistyWidth);
-      ::GetThemeMetric(kThemeMetricDisclosureButtonHeight, &twistyHeight);
-      result.SizeTo(twistyWidth, twistyHeight);
-      break;
-    }
-
-    case StyleAppearance::Treeheader:
-    case StyleAppearance::Treeheadercell: {
-      SInt32 headerHeight = 0;
-      ::GetThemeMetric(kThemeMetricListHeaderHeight, &headerHeight);
-      result.SizeTo(0, headerHeight);
-      break;
-    }
-
     case StyleAppearance::Tab: {
       result.SizeTo(0, tabHeights[miniControlSize]);
       break;
@@ -3128,6 +2975,7 @@ bool nsNativeThemeCocoa::ThemeSupportsWidget(nsPresContext* aPresContext,
     case StyleAppearance::SpinnerDownbutton:
     case StyleAppearance::Statusbar:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Searchfield:
@@ -3140,14 +2988,6 @@ bool nsNativeThemeCocoa::ThemeSupportsWidget(nsPresContext* aPresContext,
     case StyleAppearance::Tabpanels:
     case StyleAppearance::Tab:
 
-    case StyleAppearance::Treetwisty:
-    case StyleAppearance::Treetwistyopen:
-    case StyleAppearance::Treeview:
-    case StyleAppearance::Treeheader:
-    case StyleAppearance::Treeheadercell:
-    case StyleAppearance::Treeitem:
-    case StyleAppearance::Treeline:
-
     case StyleAppearance::Range:
       return !IsWidgetStyled(aPresContext, aFrame, aAppearance);
 
@@ -3184,6 +3024,7 @@ bool nsNativeThemeCocoa::ThemeDrawsFocusForWidget(nsIFrame*,
     case StyleAppearance::Textfield:
     case StyleAppearance::Searchfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Button:
@@ -3212,9 +3053,8 @@ bool nsNativeThemeCocoa::WidgetAppearanceDependsOnWindowFocus(
     case StyleAppearance::SpinnerDownbutton:
     case StyleAppearance::Separator:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
-    case StyleAppearance::Treeview:
-    case StyleAppearance::Treeline:
     case StyleAppearance::Textarea:
     case StyleAppearance::Listbox:
       return false;
diff --git a/widget/gtk/AsyncGtkClipboardRequest.cpp b/widget/gtk/AsyncGtkClipboardRequest.cpp
index 75801c698d..872b005bfd 100644
--- a/widget/gtk/AsyncGtkClipboardRequest.cpp
+++ b/widget/gtk/AsyncGtkClipboardRequest.cpp
@@ -17,17 +17,17 @@ AsyncGtkClipboardRequest::AsyncGtkClipboardRequest(ClipboardDataType aDataType,
 
   switch (aDataType) {
     case ClipboardDataType::Data:
-      LOGCLIP("  getting DATA MIME %s\n", aMimeType);
+      MOZ_CLIPBOARD_LOG("  getting DATA MIME %s\n", aMimeType);
       gtk_clipboard_request_contents(clipboard,
                                      gdk_atom_intern(aMimeType, FALSE),
                                      OnDataReceived, mRequest.get());
       break;
     case ClipboardDataType::Text:
-      LOGCLIP("  getting TEXT\n");
+      MOZ_CLIPBOARD_LOG("  getting TEXT\n");
       gtk_clipboard_request_text(clipboard, OnTextReceived, mRequest.get());
       break;
     case ClipboardDataType::Targets:
-      LOGCLIP("  getting TARGETS\n");
+      MOZ_CLIPBOARD_LOG("  getting TARGETS\n");
       gtk_clipboard_request_contents(clipboard,
                                      gdk_atom_intern("TARGETS", FALSE),
                                      OnDataReceived, mRequest.get());
@@ -39,9 +39,10 @@ void AsyncGtkClipboardRequest::OnDataReceived(GtkClipboard* clipboard,
                                               GtkSelectionData* selection_data,
                                               gpointer data) {
   int whichClipboard = GetGeckoClipboardType(clipboard);
-  LOGCLIP("OnDataReceived(%s) callback\n",
-          whichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                             : "clipboard");
+  MOZ_CLIPBOARD_LOG("OnDataReceived(%s) callback\n",
+                    whichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
   static_cast<Request*>(data)->Complete(selection_data);
 }
 
@@ -49,14 +50,16 @@ void AsyncGtkClipboardRequest::OnTextReceived(GtkClipboard* clipboard,
                                               const gchar* text,
                                               gpointer data) {
   int whichClipboard = GetGeckoClipboardType(clipboard);
-  LOGCLIP("OnTextReceived(%s) callback\n",
-          whichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                             : "clipboard");
+  MOZ_CLIPBOARD_LOG("OnTextReceived(%s) callback\n",
+                    whichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
   static_cast<Request*>(data)->Complete(text);
 }
 
 void AsyncGtkClipboardRequest::Request::Complete(const void* aData) {
-  LOGCLIP("Request::Complete(), aData = %p, timedOut = %d\n", aData, mTimedOut);
+  MOZ_CLIPBOARD_LOG("Request::Complete(), aData = %p, timedOut = %d\n", aData,
+                    mTimedOut);
 
   if (mTimedOut) {
     delete this;
@@ -75,13 +78,14 @@ void AsyncGtkClipboardRequest::Request::Complete(const void* aData) {
 
   // Negative size means no data or data error.
   if (dataLength <= 0) {
-    LOGCLIP("    zero dataLength, quit.\n");
+    MOZ_CLIPBOARD_LOG("    zero dataLength, quit.\n");
     return;
   }
 
   switch (mDataType) {
     case ClipboardDataType::Targets: {
-      LOGCLIP("    getting %d bytes of clipboard targets.\n", dataLength);
+      MOZ_CLIPBOARD_LOG("    getting %d bytes of clipboard targets.\n",
+                        dataLength);
       gint n_targets = 0;
       GdkAtom* targets = nullptr;
       if (!gtk_selection_data_get_targets((GtkSelectionData*)aData, &targets,
@@ -95,16 +99,18 @@ void AsyncGtkClipboardRequest::Request::Complete(const void* aData) {
       break;
     }
     case ClipboardDataType::Text: {
-      LOGCLIP("    getting %d bytes of text.\n", dataLength);
+      MOZ_CLIPBOARD_LOG("    getting %d bytes of text.\n", dataLength);
       mData->SetText(Span(static_cast<const char*>(aData), dataLength));
-      LOGCLIP("    done, mClipboardData = %p\n", mData->AsSpan().data());
+      MOZ_CLIPBOARD_LOG("    done, mClipboardData = %p\n",
+                        mData->AsSpan().data());
       break;
     }
     case ClipboardDataType::Data: {
-      LOGCLIP("    getting %d bytes of data.\n", dataLength);
+      MOZ_CLIPBOARD_LOG("    getting %d bytes of data.\n", dataLength);
       mData->SetData(Span(gtk_selection_data_get_data((GtkSelectionData*)aData),
                           dataLength));
-      LOGCLIP("    done, mClipboardData = %p\n", mData->AsSpan().data());
+      MOZ_CLIPBOARD_LOG("    done, mClipboardData = %p\n",
+                        mData->AsSpan().data());
       break;
     }
   }
diff --git a/widget/gtk/GfxInfo.cpp b/widget/gtk/GfxInfo.cpp
index 457b2c72ce..9c4faa26bb 100644
--- a/widget/gtk/GfxInfo.cpp
+++ b/widget/gtk/GfxInfo.cpp
@@ -1042,30 +1042,14 @@ const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
 
     ////////////////////////////////////
     // FEATURE_DMABUF_SURFACE_EXPORT
-    // Disabled due to:
+    // Disabled on all Mesa drivers due to various issue, among them:
     // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6666
     // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6796
-    APPEND_TO_DRIVER_BLOCKLIST_EXT(
-        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
-        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::AtiAll,
-        nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
-        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
-        V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
-
-    // Disabled due to:
     // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6688
-    APPEND_TO_DRIVER_BLOCKLIST_EXT(
-        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
-        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::IntelAll,
-        nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
-        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
-        V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
-
-    // Disabled due to:
     // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6988
     APPEND_TO_DRIVER_BLOCKLIST_EXT(
         OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
-        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::QualcommAll,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::All,
         nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
         nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
         V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
diff --git a/widget/gtk/GtkCompositorWidget.cpp b/widget/gtk/GtkCompositorWidget.cpp
index 073ad5248f..50eb90a0c8 100644
--- a/widget/gtk/GtkCompositorWidget.cpp
+++ b/widget/gtk/GtkCompositorWidget.cpp
@@ -141,15 +141,12 @@ bool GtkCompositorWidget::SetEGLNativeWindowSize(
 }
 
 LayoutDeviceIntRegion GtkCompositorWidget::GetTransparentRegion() {
-  // We need to clear target buffer alpha values of popup windows as
-  // SW-WR paints with alpha blending (see Bug 1674473).
-  if (!mWidget || mWidget->IsPopup()) {
-    return LayoutDeviceIntRect(LayoutDeviceIntPoint(0, 0), GetClientSize());
+  LayoutDeviceIntRegion fullRegion(
+      LayoutDeviceIntRect(LayoutDeviceIntPoint(), GetClientSize()));
+  if (mWidget) {
+    fullRegion.SubOut(mWidget->GetOpaqueRegion());
   }
-
-  // Clear background of titlebar area to render titlebar
-  // transparent corners correctly.
-  return mWidget->GetTitlebarRect();
+  return fullRegion;
 }
 
 #ifdef MOZ_WAYLAND
diff --git a/widget/gtk/MozContainerWayland.cpp b/widget/gtk/MozContainerWayland.cpp
index 39e8a48390..3a4660f4e0 100644
--- a/widget/gtk/MozContainerWayland.cpp
+++ b/widget/gtk/MozContainerWayland.cpp
@@ -84,7 +84,8 @@ using namespace mozilla::widget;
 static bool moz_container_wayland_surface_create_locked(
     const MutexAutoLock& aProofOfLock, MozContainer* container);
 static void moz_container_wayland_set_opaque_region_locked(
-    const MutexAutoLock& aProofOfLock, MozContainer* container);
+    const MutexAutoLock& aProofOfLock, MozContainer* container,
+    const LayoutDeviceIntRegion&);
 
 // Lock mozcontainer and get wayland surface of it. You need to pair with
 // moz_container_wayland_surface_unlock() even
@@ -413,7 +414,10 @@ gboolean moz_container_wayland_map_event(GtkWidget* widget,
   nsWindow* window = moz_container_get_nsWindow(MOZ_CONTAINER(widget));
   moz_container_wayland_set_scale_factor_locked(lock, MOZ_CONTAINER(widget),
                                                 window->GdkCeiledScaleFactor());
-  moz_container_wayland_set_opaque_region_locked(lock, MOZ_CONTAINER(widget));
+  if (container->data.wl_container.opaque_region_needs_updates) {
+    moz_container_wayland_set_opaque_region_locked(lock, container,
+                                                   window->GetOpaqueRegion());
+  }
   moz_container_clear_input_region(MOZ_CONTAINER(widget));
   moz_container_wayland_invalidate(MOZ_CONTAINER(widget));
   return FALSE;
@@ -456,7 +460,10 @@ void moz_container_wayland_size_allocate(GtkWidget* widget,
     nsWindow* window = moz_container_get_nsWindow(container);
     moz_container_wayland_set_scale_factor_locked(
         lock, container, window->GdkCeiledScaleFactor());
-    moz_container_wayland_set_opaque_region_locked(lock, container);
+    if (container->data.wl_container.opaque_region_needs_updates) {
+      moz_container_wayland_set_opaque_region_locked(lock, container,
+                                                     window->GetOpaqueRegion());
+    }
     moz_container_wayland_move_locked(lock, container, allocation->x,
                                       allocation->y);
     moz_container_clear_input_region(container);
@@ -465,54 +472,28 @@ void moz_container_wayland_size_allocate(GtkWidget* widget,
   }
 }
 
-static wl_region* moz_container_wayland_create_opaque_region(
-    int aX, int aY, int aWidth, int aHeight, int aCornerRadius) {
-  struct wl_compositor* compositor = WaylandDisplayGet()->GetCompositor();
-  wl_region* region = wl_compositor_create_region(compositor);
-  wl_region_add(region, aX, aY, aWidth, aHeight);
-  if (aCornerRadius) {
-    wl_region_subtract(region, aX, aY, aCornerRadius, aCornerRadius);
-    wl_region_subtract(region, aX + aWidth - aCornerRadius, aY, aCornerRadius,
-                       aCornerRadius);
-    wl_region_subtract(region, aX, aY + aHeight - aCornerRadius, aCornerRadius,
-                       aCornerRadius);
-    wl_region_subtract(region, aX + aWidth - aCornerRadius,
-                       aY + aHeight - aCornerRadius, aCornerRadius,
-                       aCornerRadius);
-  }
-  return region;
-}
-
 static void moz_container_wayland_set_opaque_region_locked(
-    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+    const MutexAutoLock& aProofOfLock, MozContainer* container,
+    const LayoutDeviceIntRegion& aRegion) {
   MozContainerWayland* wl_container = &container->data.wl_container;
-
-  if (!wl_container->opaque_region_needs_updates) {
+  MOZ_ASSERT(wl_container->opaque_region_needs_updates);
+  if (!wl_container->surface) {
     return;
   }
 
+  wl_container->opaque_region_needs_updates = false;
   if (!wl_container->opaque_region_used) {
-    wl_container->opaque_region_needs_updates = false;
     return;
   }
 
-  GtkAllocation allocation;
-  gtk_widget_get_allocation(GTK_WIDGET(container), &allocation);
-
-  wl_region* region = moz_container_wayland_create_opaque_region(
-      0, 0, allocation.width, allocation.height,
-      wl_container->opaque_region_corner_radius);
+  wl_region* region =
+      wl_compositor_create_region(WaylandDisplayGet()->GetCompositor());
+  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
+    const auto& rect = iter.Get();
+    wl_region_add(region, rect.x, rect.y, rect.Width(), rect.Height());
+  }
   wl_surface_set_opaque_region(wl_container->surface, region);
   wl_region_destroy(region);
-  wl_container->opaque_region_needs_updates = false;
-}
-
-static void moz_container_wayland_set_opaque_region(MozContainer* container) {
-  MozContainerWayland* wl_container = &container->data.wl_container;
-  MutexAutoLock lock(wl_container->container_lock);
-  if (wl_container->surface) {
-    moz_container_wayland_set_opaque_region_locked(lock, container);
-  }
 }
 
 static void moz_container_wayland_surface_set_scale_locked(
@@ -757,17 +738,18 @@ gboolean moz_container_wayland_has_egl_window(MozContainer* container) {
   return !!container->data.wl_container.eglwindow;
 }
 
-void moz_container_wayland_update_opaque_region(MozContainer* container,
-                                                int corner_radius) {
+void moz_container_wayland_update_opaque_region(MozContainer* container) {
   MozContainerWayland* wl_container = &container->data.wl_container;
+  MutexAutoLock lock(wl_container->container_lock);
   wl_container->opaque_region_needs_updates = true;
-  wl_container->opaque_region_corner_radius = corner_radius;
 
   // When GL compositor / WebRender is used,
   // moz_container_wayland_get_egl_window() is called only once when window
   // is created or resized so update opaque region now.
   if (moz_container_wayland_has_egl_window(container)) {
-    moz_container_wayland_set_opaque_region(container);
+    nsWindow* window = moz_container_get_nsWindow(container);
+    moz_container_wayland_set_opaque_region_locked(lock, container,
+                                                   window->GetOpaqueRegion());
   }
 }
 
diff --git a/widget/gtk/MozContainerWayland.h b/widget/gtk/MozContainerWayland.h
index 068c674256..6a33df2642 100644
--- a/widget/gtk/MozContainerWayland.h
+++ b/widget/gtk/MozContainerWayland.h
@@ -42,7 +42,6 @@ struct MozContainerWayland {
   struct wp_viewport* viewport = nullptr;
   struct wp_fractional_scale_v1* fractional_scale = nullptr;
   gboolean opaque_region_needs_updates = false;
-  int opaque_region_corner_radius = 0;
   gboolean opaque_region_used = false;
   gboolean ready_to_draw = false;
   gboolean commit_to_parent = false;
@@ -97,8 +96,7 @@ void moz_container_wayland_add_or_fire_initial_draw_callback(
 void moz_container_wayland_clear_initial_draw_callback(MozContainer* container);
 
 wl_surface* moz_gtk_widget_get_wl_surface(GtkWidget* aWidget);
-void moz_container_wayland_update_opaque_region(MozContainer* container,
-                                                int corner_radius);
+void moz_container_wayland_update_opaque_region(MozContainer* container);
 gboolean moz_container_wayland_can_draw(MozContainer* container);
 double moz_container_wayland_get_scale(MozContainer* container);
 double moz_container_wayland_get_fractional_scale(MozContainer* container);
diff --git a/widget/gtk/WidgetStyleCache.cpp b/widget/gtk/WidgetStyleCache.cpp
index 13b194a64e..b3d9bfcbbd 100644
--- a/widget/gtk/WidgetStyleCache.cpp
+++ b/widget/gtk/WidgetStyleCache.cpp
@@ -1079,11 +1079,6 @@ static GtkStyleContext* GetCssNodeStyleInternal(WidgetNodeType aNodeType) {
       // TODO - create from CSS node
       style = CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_VIEW);
       break;
-    case MOZ_GTK_TREEVIEW_EXPANDER:
-      // TODO - create from CSS node
-      style =
-          CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_EXPANDER);
-      break;
     case MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL:
       style = CreateChildCSSNode("separator", MOZ_GTK_SPLITTER_HORIZONTAL);
       break;
@@ -1218,10 +1213,6 @@ static GtkStyleContext* GetWidgetStyleInternal(WidgetNodeType aNodeType) {
     case MOZ_GTK_TREEVIEW_VIEW:
       style = CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_VIEW);
       break;
-    case MOZ_GTK_TREEVIEW_EXPANDER:
-      style =
-          CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_EXPANDER);
-      break;
     case MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL:
       style = CreateSubStyleWithClass(MOZ_GTK_SPLITTER_HORIZONTAL,
                                       GTK_STYLE_CLASS_PANE_SEPARATOR);
diff --git a/widget/gtk/WindowSurfaceProvider.cpp b/widget/gtk/WindowSurfaceProvider.cpp
index c8b2c5a7d6..204718bd49 100644
--- a/widget/gtk/WindowSurfaceProvider.cpp
+++ b/widget/gtk/WindowSurfaceProvider.cpp
@@ -12,6 +12,7 @@
 #include "mozilla/layers/LayersTypes.h"
 #include "nsWindow.h"
 #include "mozilla/ScopeExit.h"
+#include "WidgetUtilsGtk.h"
 
 #ifdef MOZ_WAYLAND
 #  include "mozilla/StaticPrefs_widget.h"
diff --git a/widget/gtk/gtk3drawing.cpp b/widget/gtk/gtk3drawing.cpp
index 122b43d688..c67716b90e 100644
--- a/widget/gtk/gtk3drawing.cpp
+++ b/widget/gtk/gtk3drawing.cpp
@@ -260,7 +260,8 @@ gint moz_gtk_splitter_get_metrics(gint orientation, gint* size) {
 }
 
 static void CalculateToolbarButtonMetrics(WidgetNodeType aAppearance,
-                                          ToolbarButtonGTKMetrics* aMetrics) {
+                                          ToolbarButtonGTKMetrics* aMetrics,
+                                          gint* aMaxInlineMargin) {
   gint iconWidth, iconHeight;
   if (!gtk_icon_size_lookup(GTK_ICON_SIZE_MENU, &iconWidth, &iconHeight)) {
     NS_WARNING("Failed to get Gtk+ icon size for titlebar button!");
@@ -292,6 +293,11 @@ static void CalculateToolbarButtonMetrics(WidgetNodeType aAppearance,
   aMetrics->iconXPosition = (width - iconWidth) / 2;
   aMetrics->iconYPosition = (height - iconHeight) / 2;
   aMetrics->minSizeWithBorder = {width, height};
+
+  GtkBorder margin = {0};
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &margin);
+  *aMaxInlineMargin = std::max(*aMaxInlineMargin, margin.left + margin.right);
 }
 
 size_t GetGtkHeaderBarButtonLayout(Span<ButtonLayout> aButtonLayout,
@@ -353,8 +359,7 @@ static void EnsureToolbarMetrics() {
   if (sToolbarMetrics.initialized) {
     return;
   }
-  // Make sure we have clean cache after theme reset, etc.
-  memset(&sToolbarMetrics, 0, sizeof(sToolbarMetrics));
+  sToolbarMetrics = {};
 
   // Calculate titlebar button visibility and positions.
   ButtonLayout buttonLayout[TOOLBAR_BUTTONS];
@@ -364,9 +369,15 @@ static void EnsureToolbarMetrics() {
   for (const auto& layout : Span(buttonLayout, activeButtonNums)) {
     int buttonIndex = layout.mType - MOZ_GTK_HEADER_BAR_BUTTON_CLOSE;
     ToolbarButtonGTKMetrics* metrics = &sToolbarMetrics.button[buttonIndex];
-    CalculateToolbarButtonMetrics(layout.mType, metrics);
+    CalculateToolbarButtonMetrics(layout.mType, metrics,
+                                  &sToolbarMetrics.inlineSpacing);
   }
 
+  // Account for the spacing property in the header bar.
+  // Default to 6 pixels (gtk/gtkheaderbar.c)
+  gint spacing = 6;
+  g_object_get(GetWidget(MOZ_GTK_HEADER_BAR), "spacing", &spacing, nullptr);
+  sToolbarMetrics.inlineSpacing += spacing;
   sToolbarMetrics.initialized = true;
 }
 
@@ -380,6 +391,11 @@ const ToolbarButtonGTKMetrics* GetToolbarButtonMetrics(
   return sToolbarMetrics.button + buttonIndex;
 }
 
+gint moz_gtk_get_titlebar_button_spacing() {
+  EnsureToolbarMetrics();
+  return sToolbarMetrics.inlineSpacing;
+}
+
 static gint moz_gtk_window_decoration_paint(cairo_t* cr,
                                             const GdkRectangle* rect,
                                             GtkWidgetState* state,
@@ -937,54 +953,7 @@ static gint moz_gtk_treeview_paint(cairo_t* cr, GdkRectangle* rect,
   return MOZ_GTK_SUCCESS;
 }
 
-static gint moz_gtk_tree_header_cell_paint(cairo_t* cr,
-                                           const GdkRectangle* aRect,
-                                           GtkWidgetState* state,
-                                           gboolean isSorted,
-                                           GtkTextDirection direction) {
-  moz_gtk_button_paint(cr, aRect, state, GTK_RELIEF_NORMAL,
-                       GetWidget(MOZ_GTK_TREE_HEADER_CELL), direction);
-  return MOZ_GTK_SUCCESS;
-}
-
-/* See gtk_expander_paint() for reference.
- */
-static gint moz_gtk_treeview_expander_paint(cairo_t* cr, GdkRectangle* rect,
-                                            GtkWidgetState* state,
-                                            GtkExpanderStyle expander_state,
-                                            GtkTextDirection direction) {
-  /* Because the frame we get is of the entire treeview, we can't get the
-   * precise event state of one expander, thus rendering hover and active
-   * feedback useless. */
-  GtkStateFlags state_flags =
-      state->disabled ? GTK_STATE_FLAG_INSENSITIVE : GTK_STATE_FLAG_NORMAL;
-
-  if (state->inHover)
-    state_flags =
-        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_PRELIGHT);
-  if (state->selected)
-    state_flags =
-        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_SELECTED);
-
-  /* GTK_STATE_FLAG_ACTIVE controls expanded/colapsed state rendering
-   * in gtk_render_expander()
-   */
-  if (expander_state == GTK_EXPANDER_EXPANDED)
-    state_flags =
-        static_cast<GtkStateFlags>(state_flags | checkbox_check_state);
-  else
-    state_flags =
-        static_cast<GtkStateFlags>(state_flags & ~(checkbox_check_state));
-
-  GtkStyleContext* style = GetStyleContext(
-      MOZ_GTK_TREEVIEW_EXPANDER, state->image_scale, direction, state_flags);
-  gtk_render_expander(style, cr, rect->x, rect->y, rect->width, rect->height);
-
-  return MOZ_GTK_SUCCESS;
-}
-
-/* See gtk_separator_draw() for reference.
- */
+/* See gtk_separator_draw() for reference. */
 static gint moz_gtk_combo_box_paint(cairo_t* cr, const GdkRectangle* aRect,
                                     GtkWidgetState* state,
                                     GtkTextDirection direction) {
@@ -1572,18 +1541,6 @@ gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
       moz_gtk_add_style_border(style, left, top, right, bottom);
       return MOZ_GTK_SUCCESS;
     }
-    case MOZ_GTK_TREE_HEADER_CELL: {
-      /* A Tree Header in GTK is just a different styled button
-       * It must be placed in a TreeView for getting the correct style
-       * assigned.
-       * That is why the following code is the same as for MOZ_GTK_BUTTON.
-       * */
-      *left = *top = *right = *bottom = gtk_container_get_border_width(
-          GTK_CONTAINER(GetWidget(MOZ_GTK_TREE_HEADER_CELL)));
-      style = GetStyleContext(MOZ_GTK_TREE_HEADER_CELL);
-      moz_gtk_add_border_padding(style, left, top, right, bottom);
-      return MOZ_GTK_SUCCESS;
-    }
     case MOZ_GTK_DROPDOWN: {
       /* We need to account for the arrow on the dropdown, so text
        * doesn't come too close to the arrow, or in some cases spill
@@ -1669,7 +1626,6 @@ gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
     case MOZ_GTK_PROGRESS_CHUNK:
     case MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE:
     case MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE:
-    case MOZ_GTK_TREEVIEW_EXPANDER:
     case MOZ_GTK_HEADER_BAR:
     case MOZ_GTK_HEADER_BAR_MAXIMIZED:
     case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
@@ -1777,18 +1733,6 @@ void moz_gtk_get_arrow_size(WidgetNodeType widgetType, gint* width,
   }
 }
 
-gint moz_gtk_get_expander_size(gint* size) {
-  GtkStyleContext* style = GetStyleContext(MOZ_GTK_EXPANDER);
-  gtk_style_context_get_style(style, "expander-size", size, NULL);
-  return MOZ_GTK_SUCCESS;
-}
-
-gint moz_gtk_get_treeview_expander_size(gint* size) {
-  GtkStyleContext* style = GetStyleContext(MOZ_GTK_TREEVIEW);
-  gtk_style_context_get_style(style, "expander-size", size, NULL);
-  return MOZ_GTK_SUCCESS;
-}
-
 void moz_gtk_get_entry_min_height(gint* min_content_height,
                                   gint* border_padding_height) {
   GtkStyleContext* style = GetStyleContext(MOZ_GTK_ENTRY);
@@ -2057,11 +2001,6 @@ gint moz_gtk_widget_paint(WidgetNodeType widget, cairo_t* cr,
     }
     case MOZ_GTK_TREEVIEW:
       return moz_gtk_treeview_paint(cr, rect, state, direction);
-    case MOZ_GTK_TREE_HEADER_CELL:
-      return moz_gtk_tree_header_cell_paint(cr, rect, state, flags, direction);
-    case MOZ_GTK_TREEVIEW_EXPANDER:
-      return moz_gtk_treeview_expander_paint(
-          cr, rect, state, (GtkExpanderStyle)flags, direction);
     case MOZ_GTK_ENTRY:
     case MOZ_GTK_DROPDOWN_ENTRY: {
       GtkStyleContext* style =
diff --git a/widget/gtk/gtkdrawing.h b/widget/gtk/gtkdrawing.h
index 4ca226d9c7..227a33d9a9 100644
--- a/widget/gtk/gtkdrawing.h
+++ b/widget/gtk/gtkdrawing.h
@@ -69,38 +69,39 @@ struct MozGtkSize {
   }
 };
 
-typedef struct {
+struct ToggleGTKMetrics {
   bool initialized;
   MozGtkSize minSizeWithBorder;
   GtkBorder borderAndPadding;
-} ToggleGTKMetrics;
+};
 
-typedef struct {
-  MozGtkSize minSizeWithBorder;
-  gint iconXPosition;
-  gint iconYPosition;
-} ToolbarButtonGTKMetrics;
+struct ToolbarButtonGTKMetrics {
+  MozGtkSize minSizeWithBorder{};
+  gint iconXPosition = 0;
+  gint iconYPosition = 0;
+};
 
 #define TOOLBAR_BUTTONS 3
-typedef struct {
-  bool initialized;
+struct ToolbarGTKMetrics {
+  bool initialized = false;
+  gint inlineSpacing = 0;
   ToolbarButtonGTKMetrics button[TOOLBAR_BUTTONS];
-} ToolbarGTKMetrics;
+};
 
-typedef struct {
+struct CSDWindowDecorationSize {
   bool initialized;
   GtkBorder decorationSize;
-} CSDWindowDecorationSize;
+};
 
 /** flags for tab state **/
-typedef enum {
+enum GtkTabFlags {
   /* first eight bits are used to pass a margin */
   MOZ_GTK_TAB_MARGIN_MASK = 0xFF,
   /* the first tab in the group */
   MOZ_GTK_TAB_FIRST = 1 << 9,
   /* the selected tab */
   MOZ_GTK_TAB_SELECTED = 1 << 10
-} GtkTabFlags;
+};
 
 /*** result/error codes ***/
 #define MOZ_GTK_SUCCESS 0
@@ -211,8 +212,6 @@ enum WidgetNodeType : int {
   MOZ_GTK_TREEVIEW_VIEW,
   /* Paints treeheader cells */
   MOZ_GTK_TREE_HEADER_CELL,
-  /* Paints an expander for a GtkTreeView */
-  MOZ_GTK_TREEVIEW_EXPANDER,
   /* Paints the background of menus, context menus. */
   MOZ_GTK_MENUPOPUP,
   /* Menubar for -moz-headerbar colors */
@@ -458,22 +457,6 @@ void moz_gtk_get_entry_min_height(gint* min_content_height,
 gint moz_gtk_get_toolbar_separator_width(gint* size);
 
 /**
- * Get the size of a regular GTK expander that shows/hides content
- * size:    [OUT] the size of the GTK expander, size = width = height.
- *
- * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
- */
-gint moz_gtk_get_expander_size(gint* size);
-
-/**
- * Get the size of a treeview's expander (we call them twisties)
- * size:    [OUT] the size of the GTK expander, size = width = height.
- *
- * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
- */
-gint moz_gtk_get_treeview_expander_size(gint* size);
-
-/**
  * Get the desired size of a splitter
  * orientation:   [IN]  GTK_ORIENTATION_HORIZONTAL or GTK_ORIENTATION_VERTICAL
  * size:          [OUT] width or height of the splitter handle
@@ -493,6 +476,8 @@ gint moz_gtk_get_tab_thickness(WidgetNodeType aNodeType);
 const ToolbarButtonGTKMetrics* GetToolbarButtonMetrics(
     WidgetNodeType aAppearance);
 
+gint moz_gtk_get_titlebar_button_spacing();
+
 /**
  * Get toolbar button layout.
  * aButtonLayout:  [OUT] An array which will be filled by ButtonLayout
diff --git a/widget/gtk/nsAppShell.cpp b/widget/gtk/nsAppShell.cpp
index d26b43737d..652801fe69 100644
--- a/widget/gtk/nsAppShell.cpp
+++ b/widget/gtk/nsAppShell.cpp
@@ -53,7 +53,6 @@ LazyLogModule gWidgetWaylandLog("WidgetWayland");
 LazyLogModule gWidgetPopupLog("WidgetPopup");
 LazyLogModule gWidgetVsync("WidgetVsync");
 LazyLogModule gDmabufLog("Dmabuf");
-LazyLogModule gClipboardLog("WidgetClipboard");
 
 static GPollFunc sPollFunc;
 
diff --git a/widget/gtk/nsClipboard.cpp b/widget/gtk/nsClipboard.cpp
index 571b43f1cc..206c8ddeb3 100644
--- a/widget/gtk/nsClipboard.cpp
+++ b/widget/gtk/nsClipboard.cpp
@@ -88,7 +88,8 @@ static void SetTransferableData(nsITransferable* aTransferable,
                                 const nsACString& aFlavor,
                                 const char* aClipboardData,
                                 uint32_t aClipboardDataLength) {
-  LOGCLIP("SetTransferableData MIME %s\n", PromiseFlatCString(aFlavor).get());
+  MOZ_CLIPBOARD_LOG("SetTransferableData MIME %s\n",
+                    PromiseFlatCString(aFlavor).get());
   nsCOMPtr<nsISupports> wrapper;
   nsPrimitiveHelpers::CreatePrimitiveForData(
       aFlavor, aClipboardData, aClipboardDataLength, getter_AddRefs(wrapper));
@@ -161,29 +162,30 @@ int GetGeckoClipboardType(GtkClipboard* aGtkClipboard) {
 void nsRetrievalContext::ClearCachedTargetsClipboard(GtkClipboard* aClipboard,
                                                      GdkEvent* aEvent,
                                                      gpointer data) {
-  LOGCLIP("nsRetrievalContext::ClearCachedTargetsClipboard()");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContext::ClearCachedTargetsClipboard()");
   sClipboardTargets.Clear();
 }
 
 void nsRetrievalContext::ClearCachedTargetsPrimary(GtkClipboard* aClipboard,
                                                    GdkEvent* aEvent,
                                                    gpointer data) {
-  LOGCLIP("nsRetrievalContext::ClearCachedTargetsPrimary()");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContext::ClearCachedTargetsPrimary()");
   sPrimaryTargets.Clear();
 }
 
 ClipboardTargets nsRetrievalContext::GetTargets(int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContext::GetTargets(%s)\n",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContext::GetTargets(%s)\n",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
   ClipboardTargets& storedTargets =
       (aWhichClipboard == nsClipboard::kSelectionClipboard) ? sPrimaryTargets
                                                             : sClipboardTargets;
   if (!storedTargets) {
-    LOGCLIP("  getting targets from system");
+    MOZ_CLIPBOARD_LOG("  getting targets from system");
     storedTargets.Set(GetTargetsImpl(aWhichClipboard));
   } else {
-    LOGCLIP("  using cached targets");
+    MOZ_CLIPBOARD_LOG("  using cached targets");
   }
   return storedTargets.Clone();
 }
@@ -249,7 +251,7 @@ nsClipboard::Observe(nsISupports* aSubject, const char* aTopic,
   // runnable.
   return SchedulerGroup::Dispatch(
       NS_NewRunnableFunction("gtk_clipboard_store()", []() {
-        LOGCLIP("nsClipboard storing clipboard content\n");
+        MOZ_CLIPBOARD_LOG("nsClipboard storing clipboard content\n");
         gtk_clipboard_store(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
       }));
 }
@@ -269,8 +271,9 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
     return NS_OK;
   }
 
-  LOGCLIP("nsClipboard::SetNativeClipboardData (%s)\n",
-          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::SetNativeClipboardData (%s)\n",
+      aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
 
   // List of suported targets
   GtkTargetList* list = gtk_target_list_new(nullptr, 0);
@@ -279,7 +282,7 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
   nsTArray<nsCString> flavors;
   nsresult rv = aTransferable->FlavorsTransferableCanExport(flavors);
   if (NS_FAILED(rv)) {
-    LOGCLIP("    FlavorsTransferableCanExport failed!\n");
+    MOZ_CLIPBOARD_LOG("    FlavorsTransferableCanExport failed!\n");
     // Fall through.  |gtkTargets| will be null below.
   }
 
@@ -287,11 +290,11 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
   bool imagesAdded = false;
   for (uint32_t i = 0; i < flavors.Length(); i++) {
     nsCString& flavorStr = flavors[i];
-    LOGCLIP("    processing target %s\n", flavorStr.get());
+    MOZ_CLIPBOARD_LOG("    processing target %s\n", flavorStr.get());
 
     // Special case text/plain since we can handle all of the string types.
     if (flavorStr.EqualsLiteral(kTextMime)) {
-      LOGCLIP("    adding TEXT targets\n");
+      MOZ_CLIPBOARD_LOG("    adding TEXT targets\n");
       gtk_target_list_add_text_targets(list, 0);
       continue;
     }
@@ -300,7 +303,7 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
       // Don't bother adding image targets twice
       if (!imagesAdded) {
         // accept any writable image type
-        LOGCLIP("    adding IMAGE targets\n");
+        MOZ_CLIPBOARD_LOG("    adding IMAGE targets\n");
         gtk_target_list_add_image_targets(list, 0, TRUE);
         imagesAdded = true;
       }
@@ -308,14 +311,14 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
     }
 
     if (flavorStr.EqualsLiteral(kFileMime)) {
-      LOGCLIP("    adding text/uri-list target\n");
+      MOZ_CLIPBOARD_LOG("    adding text/uri-list target\n");
       GdkAtom atom = gdk_atom_intern(kURIListMime, FALSE);
       gtk_target_list_add(list, atom, 0, 0);
       continue;
     }
 
     // Add this to our list of valid targets
-    LOGCLIP("    adding OTHER target %s\n", flavorStr.get());
+    MOZ_CLIPBOARD_LOG("    adding OTHER target %s\n", flavorStr.get());
     GdkAtom atom = gdk_atom_intern(flavorStr.get(), FALSE);
     gtk_target_list_add(list, atom, 0, 0);
   }
@@ -328,7 +331,7 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
   GtkTargetEntry* gtkTargets =
       gtk_target_table_new_from_list(list, &numTargets);
   if (!gtkTargets || numTargets == 0) {
-    LOGCLIP(
+    MOZ_CLIPBOARD_LOG(
         "    gtk_target_table_new_from_list() failed or empty list of "
         "targets!\n");
     // Clear references to the any old data and let GTK know that it is no
@@ -356,7 +359,7 @@ nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
 
     rv = NS_OK;
   } else {
-    LOGCLIP("    gtk_clipboard_set_with_data() failed!\n");
+    MOZ_CLIPBOARD_LOG("    gtk_clipboard_set_with_data() failed!\n");
     EmptyNativeClipboardData(aWhichClipboard);
     rv = NS_ERROR_FAILURE;
   }
@@ -390,11 +393,11 @@ static bool IsMIMEAtFlavourList(const nsTArray<nsCString>& aFlavourList,
 // So if clipboard contains images only remove text MIME offer.
 bool nsClipboard::FilterImportedFlavors(int32_t aWhichClipboard,
                                         nsTArray<nsCString>& aFlavors) {
-  LOGCLIP("nsClipboard::FilterImportedFlavors");
+  MOZ_CLIPBOARD_LOG("nsClipboard::FilterImportedFlavors");
 
   auto targets = mContext->GetTargets(aWhichClipboard);
   if (!targets) {
-    LOGCLIP("    X11: no targes at clipboard (null), quit.\n");
+    MOZ_CLIPBOARD_LOG("    X11: no targes at clipboard (null), quit.\n");
     return true;
   }
 
@@ -419,7 +422,8 @@ bool nsClipboard::FilterImportedFlavors(int32_t aWhichClipboard,
     }
     // We have some other MIME type on clipboard which can be hopefully
     // converted to text without any problem.
-    LOGCLIP("    X11: text types in clipboard, no need to filter them.\n");
+    MOZ_CLIPBOARD_LOG(
+        "    X11: text types in clipboard, no need to filter them.\n");
     return true;
   }
 
@@ -436,9 +440,9 @@ bool nsClipboard::FilterImportedFlavors(int32_t aWhichClipboard,
   }
   aFlavors.SwapElements(clipboardFlavors);
 #ifdef MOZ_LOGGING
-  LOGCLIP("    X11: Flavors which match clipboard content:\n");
+  MOZ_CLIPBOARD_LOG("    X11: Flavors which match clipboard content:\n");
   for (uint32_t i = 0; i < aFlavors.Length(); i++) {
-    LOGCLIP("    %s\n", aFlavors[i].get());
+    MOZ_CLIPBOARD_LOG("    %s\n", aFlavors[i].get());
   }
 #endif
   return true;
@@ -452,13 +456,13 @@ static nsresult GetTransferableFlavors(nsITransferable* aTransferable,
   // Get a list of flavors this transferable can import
   nsresult rv = aTransferable->FlavorsTransferableCanImport(aFlavors);
   if (NS_FAILED(rv)) {
-    LOGCLIP("  FlavorsTransferableCanImport falied!\n");
+    MOZ_CLIPBOARD_LOG("  FlavorsTransferableCanImport falied!\n");
     return rv;
   }
 #ifdef MOZ_LOGGING
-  LOGCLIP("  Flavors which can be imported:");
+  MOZ_CLIPBOARD_LOG("  Flavors which can be imported:");
   for (const auto& flavor : aFlavors) {
-    LOGCLIP("    %s", flavor.get());
+    MOZ_CLIPBOARD_LOG("    %s", flavor.get());
   }
 #endif
   return NS_OK;
@@ -476,7 +480,7 @@ static bool TransferableSetFile(nsITransferable* aTransferable,
       rv = fileURL->GetFile(getter_AddRefs(file));
       if (NS_SUCCEEDED(rv)) {
         aTransferable->SetTransferData(kFileMime, file);
-        LOGCLIP("  successfully set file to clipboard\n");
+        MOZ_CLIPBOARD_LOG("  successfully set file to clipboard\n");
         return true;
       }
     }
@@ -492,17 +496,20 @@ static bool TransferableSetHTML(nsITransferable* aTransferable,
   nsAutoCString charset;
   if (!GetHTMLCharset(aData, charset)) {
     // Fall back to utf-8 in case html/data is missing kHTMLMarkupPrefix.
-    LOGCLIP("Failed to get html/text encoding, fall back to utf-8.\n");
+    MOZ_CLIPBOARD_LOG(
+        "Failed to get html/text encoding, fall back to utf-8.\n");
     charset.AssignLiteral("utf-8");
   }
 
-  LOGCLIP("TransferableSetHTML: HTML detected charset %s", charset.get());
+  MOZ_CLIPBOARD_LOG("TransferableSetHTML: HTML detected charset %s",
+                    charset.get());
   // app which use "text/html" to copy&paste
   // get the decoder
   auto encoding = Encoding::ForLabelNoReplacement(charset);
   if (!encoding) {
-    LOGCLIP("TransferableSetHTML: get unicode decoder error (charset: %s)",
-            charset.get());
+    MOZ_CLIPBOARD_LOG(
+        "TransferableSetHTML: get unicode decoder error (charset: %s)",
+        charset.get());
     return false;
   }
 
@@ -523,16 +530,15 @@ static bool TransferableSetHTML(nsITransferable* aTransferable,
   nsAutoString unicodeData;
   auto [rv, enc] = encoding->Decode(AsBytes(aData), unicodeData);
 #if MOZ_LOGGING
-  if (enc != UTF_8_ENCODING &&
-      MOZ_LOG_TEST(gClipboardLog, mozilla::LogLevel::Debug)) {
+  if (enc != UTF_8_ENCODING && MOZ_CLIPBOARD_LOG_ENABLED()) {
     nsCString decoderName;
     enc->Name(decoderName);
-    LOGCLIP("TransferableSetHTML: expected UTF-8 decoder but got %s",
-            decoderName.get());
+    MOZ_CLIPBOARD_LOG("TransferableSetHTML: expected UTF-8 decoder but got %s",
+                      decoderName.get());
   }
 #endif
   if (NS_FAILED(rv)) {
-    LOGCLIP("TransferableSetHTML: failed to decode HTML");
+    MOZ_CLIPBOARD_LOG("TransferableSetHTML: failed to decode HTML");
     return false;
   }
   SetTransferableData(aTransferable, mimeType,
@@ -548,8 +554,9 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
   MOZ_DIAGNOSTIC_ASSERT(
       nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
 
-  LOGCLIP("nsClipboard::GetNativeClipboardData (%s)\n",
-          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::GetNativeClipboardData (%s)\n",
+      aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
 
   // TODO: Ensure we don't re-enter here.
   if (!mContext) {
@@ -564,7 +571,7 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
   // see Bug 1611407
   if (widget::GdkIsX11Display() &&
       !FilterImportedFlavors(aWhichClipboard, flavors)) {
-    LOGCLIP("    Missing suitable clipboard data, quit.");
+    MOZ_CLIPBOARD_LOG("    Missing suitable clipboard data, quit.");
     return NS_OK;
   }
 
@@ -580,12 +587,13 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
         flavorStr.Assign(kJPEGImageMime);
       }
 
-      LOGCLIP("    Getting image %s MIME clipboard data\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    Getting image %s MIME clipboard data\n",
+                        flavorStr.get());
 
       auto clipboardData =
           mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
       if (!clipboardData) {
-        LOGCLIP("    %s type is missing\n", flavorStr.get());
+        MOZ_CLIPBOARD_LOG("    %s type is missing\n", flavorStr.get());
         continue;
       }
 
@@ -593,18 +601,19 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
       NS_NewByteInputStream(getter_AddRefs(byteStream), clipboardData.AsSpan(),
                             NS_ASSIGNMENT_COPY);
       aTransferable->SetTransferData(flavorStr.get(), byteStream);
-      LOGCLIP("    got %s MIME data\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    got %s MIME data\n", flavorStr.get());
       return NS_OK;
     }
 
     // Special case text/plain since we can convert any
     // string into text/plain
     if (flavorStr.EqualsLiteral(kTextMime)) {
-      LOGCLIP("    Getting text %s MIME clipboard data\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    Getting text %s MIME clipboard data\n",
+                        flavorStr.get());
 
       auto clipboardData = mContext->GetClipboardText(aWhichClipboard);
       if (!clipboardData) {
-        LOGCLIP("    failed to get text data\n");
+        MOZ_CLIPBOARD_LOG("    failed to get text data\n");
         // If the type was text/plain and we couldn't get
         // text off the clipboard, run the next loop
         // iteration.
@@ -617,17 +626,18 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
                           (const char*)ucs2string.BeginReading(),
                           ucs2string.Length() * 2);
 
-      LOGCLIP("    got text data, length %zd\n", ucs2string.Length());
+      MOZ_CLIPBOARD_LOG("    got text data, length %zd\n", ucs2string.Length());
       return NS_OK;
     }
 
     if (flavorStr.EqualsLiteral(kFileMime)) {
-      LOGCLIP("    Getting %s file clipboard data\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    Getting %s file clipboard data\n",
+                        flavorStr.get());
 
       auto clipboardData =
           mContext->GetClipboardData(kURIListMime, aWhichClipboard);
       if (!clipboardData) {
-        LOGCLIP("    text/uri-list type is missing\n");
+        MOZ_CLIPBOARD_LOG("    text/uri-list type is missing\n");
         continue;
       }
 
@@ -638,19 +648,19 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
       return NS_OK;
     }
 
-    LOGCLIP("    Getting %s MIME clipboard data\n", flavorStr.get());
+    MOZ_CLIPBOARD_LOG("    Getting %s MIME clipboard data\n", flavorStr.get());
 
     auto clipboardData =
         mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
 
 #ifdef MOZ_LOGGING
     if (!clipboardData) {
-      LOGCLIP("    %s type is missing\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    %s type is missing\n", flavorStr.get());
     }
 #endif
 
     if (clipboardData) {
-      LOGCLIP("    got %s mime type data.\n", flavorStr.get());
+      MOZ_CLIPBOARD_LOG("    got %s mime type data.\n", flavorStr.get());
 
       // Special case text/html since we can convert into UCS2
       if (flavorStr.EqualsLiteral(kHTMLMime)) {
@@ -666,7 +676,7 @@ nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
     }
   }
 
-  LOGCLIP("    failed to get clipboard content.\n");
+  MOZ_CLIPBOARD_LOG("    failed to get clipboard content.\n");
   return NS_OK;
 }
 
@@ -692,11 +702,11 @@ struct DataCallbackHandler {
         mMimeType(aMimeType),
         mDataType(aDataType) {
     MOZ_COUNT_CTOR(DataCallbackHandler);
-    LOGCLIP("DataCallbackHandler created [%p] MIME %s type %d", this,
-            mMimeType.get(), mDataType);
+    MOZ_CLIPBOARD_LOG("DataCallbackHandler created [%p] MIME %s type %d", this,
+                      mMimeType.get(), mDataType);
   }
   ~DataCallbackHandler() {
-    LOGCLIP("DataCallbackHandler deleted [%p]", this);
+    MOZ_CLIPBOARD_LOG("DataCallbackHandler deleted [%p]", this);
     MOZ_COUNT_DTOR(DataCallbackHandler);
   }
 };
@@ -704,20 +714,21 @@ struct DataCallbackHandler {
 static void AsyncGetTextImpl(nsITransferable* aTransferable,
                              int32_t aWhichClipboard,
                              nsBaseClipboard::GetDataCallback&& aCallback) {
-  LOGCLIP("AsyncGetText() type '%s'",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("AsyncGetText() type '%s'",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
 
   gtk_clipboard_request_text(
       gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
       [](GtkClipboard* aClipboard, const gchar* aText, gpointer aData) -> void {
         UniquePtr<DataCallbackHandler> ref(
             static_cast<DataCallbackHandler*>(aData));
-        LOGCLIP("AsyncGetText async handler of [%p]", aData);
+        MOZ_CLIPBOARD_LOG("AsyncGetText async handler of [%p]", aData);
 
         size_t dataLength = aText ? strlen(aText) : 0;
         if (dataLength <= 0) {
-          LOGCLIP("  quit, text is not available");
+          MOZ_CLIPBOARD_LOG("  quit, text is not available");
           ref->mDataCallback(NS_OK);
           return;
         }
@@ -728,7 +739,7 @@ static void AsyncGetTextImpl(nsITransferable* aTransferable,
         SetTransferableData(ref->mTransferable, flavor,
                             (const char*)utf16string.BeginReading(),
                             utf16string.Length() * 2);
-        LOGCLIP("  text is set, length = %d", (int)dataLength);
+        MOZ_CLIPBOARD_LOG("  text is set, length = %d", (int)dataLength);
         ref->mDataCallback(NS_OK);
       },
       new DataCallbackHandler(aTransferable, std::move(aCallback), kTextMime));
@@ -738,9 +749,10 @@ static void AsyncGetDataImpl(nsITransferable* aTransferable,
                              int32_t aWhichClipboard, const char* aMimeType,
                              DataType aDataType,
                              nsBaseClipboard::GetDataCallback&& aCallback) {
-  LOGCLIP("AsyncGetData() type '%s'",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("AsyncGetData() type '%s'",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
 
   const char* gtkMIMEType = nullptr;
   switch (aDataType) {
@@ -762,8 +774,8 @@ static void AsyncGetDataImpl(nsITransferable* aTransferable,
          gpointer aData) -> void {
         UniquePtr<DataCallbackHandler> ref(
             static_cast<DataCallbackHandler*>(aData));
-        LOGCLIP("AsyncGetData async handler [%p] MIME %s type %d", aData,
-                ref->mMimeType.get(), ref->mDataType);
+        MOZ_CLIPBOARD_LOG("AsyncGetData async handler [%p] MIME %s type %d",
+                          aData, ref->mMimeType.get(), ref->mDataType);
 
         int dataLength = gtk_selection_data_get_length(aSelection);
         if (dataLength <= 0) {
@@ -777,7 +789,7 @@ static void AsyncGetDataImpl(nsITransferable* aTransferable,
         }
         switch (ref->mDataType) {
           case DATATYPE_IMAGE: {
-            LOGCLIP("  set image clipboard data");
+            MOZ_CLIPBOARD_LOG("  set image clipboard data");
             nsCOMPtr<nsIInputStream> byteStream;
             NS_NewByteInputStream(getter_AddRefs(byteStream),
                                   Span(data, dataLength), NS_ASSIGNMENT_COPY);
@@ -786,19 +798,19 @@ static void AsyncGetDataImpl(nsITransferable* aTransferable,
             break;
           }
           case DATATYPE_FILE: {
-            LOGCLIP("  set file clipboard data");
+            MOZ_CLIPBOARD_LOG("  set file clipboard data");
             nsDependentCSubstring file(data, dataLength);
             TransferableSetFile(ref->mTransferable, file);
             break;
           }
           case DATATYPE_HTML: {
-            LOGCLIP("  html clipboard data");
+            MOZ_CLIPBOARD_LOG("  html clipboard data");
             Span dataSpan(data, dataLength);
             TransferableSetHTML(ref->mTransferable, dataSpan);
             break;
           }
           case DATATYPE_RAW: {
-            LOGCLIP("  raw clipboard data %s", ref->mMimeType.get());
+            MOZ_CLIPBOARD_LOG("  raw clipboard data %s", ref->mMimeType.get());
             SetTransferableData(ref->mTransferable, ref->mMimeType, data,
                                 dataLength);
             break;
@@ -821,7 +833,8 @@ static void AsyncGetDataFlavor(nsITransferable* aTransferable,
     if (aFlavorStr.EqualsLiteral(kJPGImageMime)) {
       aFlavorStr.Assign(kJPEGImageMime);
     }
-    LOGCLIP("  Getting image %s MIME clipboard data", aFlavorStr.get());
+    MOZ_CLIPBOARD_LOG("  Getting image %s MIME clipboard data",
+                      aFlavorStr.get());
     AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
                      DATATYPE_IMAGE, std::move(aCallback));
     return;
@@ -829,23 +842,23 @@ static void AsyncGetDataFlavor(nsITransferable* aTransferable,
   // Special case text/plain since we can convert any
   // string into text/plain
   if (aFlavorStr.EqualsLiteral(kTextMime)) {
-    LOGCLIP("  Getting unicode clipboard data");
+    MOZ_CLIPBOARD_LOG("  Getting unicode clipboard data");
     AsyncGetTextImpl(aTransferable, aWhichClipboard, std::move(aCallback));
     return;
   }
   if (aFlavorStr.EqualsLiteral(kFileMime)) {
-    LOGCLIP("  Getting file clipboard data\n");
+    MOZ_CLIPBOARD_LOG("  Getting file clipboard data\n");
     AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
                      DATATYPE_FILE, std::move(aCallback));
     return;
   }
   if (aFlavorStr.EqualsLiteral(kHTMLMime)) {
-    LOGCLIP("  Getting HTML clipboard data");
+    MOZ_CLIPBOARD_LOG("  Getting HTML clipboard data");
     AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
                      DATATYPE_HTML, std::move(aCallback));
     return;
   }
-  LOGCLIP("  Getting raw %s MIME clipboard data\n", aFlavorStr.get());
+  MOZ_CLIPBOARD_LOG("  Getting raw %s MIME clipboard data\n", aFlavorStr.get());
   AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
                    DATATYPE_RAW, std::move(aCallback));
 }
@@ -857,9 +870,10 @@ void nsClipboard::AsyncGetNativeClipboardData(nsITransferable* aTransferable,
   MOZ_DIAGNOSTIC_ASSERT(
       nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
 
-  LOGCLIP("nsClipboard::AsyncGetNativeClipboardData (%s)",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("nsClipboard::AsyncGetNativeClipboardData (%s)",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
   nsTArray<nsCString> importedFlavors;
   nsresult rv = GetTransferableFlavors(aTransferable, importedFlavors);
   if (NS_FAILED(rv)) {
@@ -874,8 +888,9 @@ void nsClipboard::AsyncGetNativeClipboardData(nsITransferable* aTransferable,
   }
 #ifdef MOZ_LOGGING
   if (flavorsNum > 1) {
-    LOGCLIP("  Only first MIME type (%s) will be imported from clipboard!",
-            importedFlavors[0].get());
+    MOZ_CLIPBOARD_LOG(
+        "  Only first MIME type (%s) will be imported from clipboard!",
+        importedFlavors[0].get());
   }
 #endif
 
@@ -894,7 +909,7 @@ void nsClipboard::AsyncGetNativeClipboardData(nsITransferable* aTransferable,
           nsTArray<nsCString> clipboardFlavors =
               std::move(aResultOrError.unwrap());
           if (!clipboardFlavors.Length()) {
-            LOGCLIP("  no flavors in clipboard, quit.");
+            MOZ_CLIPBOARD_LOG("  no flavors in clipboard, quit.");
             callback(NS_OK);
             return;
           }
@@ -914,8 +929,9 @@ nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
   MOZ_DIAGNOSTIC_ASSERT(
       nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
 
-  LOGCLIP("nsClipboard::EmptyNativeClipboardData (%s)\n",
-          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::EmptyNativeClipboardData (%s)\n",
+      aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
   if (aWhichClipboard == kSelectionClipboard) {
     if (mSelectionTransferable) {
       gtk_clipboard_clear(gtk_clipboard_get(GDK_SELECTION_PRIMARY));
@@ -947,20 +963,21 @@ static bool FlavorMatchesTarget(const nsACString& aFlavor, GdkAtom aTarget) {
     return false;
   }
   if (aFlavor.Equals(atom_name.get())) {
-    LOGCLIP("    has %s\n", atom_name.get());
+    MOZ_CLIPBOARD_LOG("    has %s\n", atom_name.get());
     return true;
   }
   // X clipboard supports image/jpeg, but we want to emulate support
   // for image/jpg as well
   if (aFlavor.EqualsLiteral(kJPGImageMime) &&
       !strcmp(atom_name.get(), kJPEGImageMime)) {
-    LOGCLIP("    has image/jpg\n");
+    MOZ_CLIPBOARD_LOG("    has image/jpg\n");
     return true;
   }
   // application/x-moz-file should be treated like text/uri-list
   if (aFlavor.EqualsLiteral(kFileMime) &&
       !strcmp(atom_name.get(), kURIListMime)) {
-    LOGCLIP("    has text/uri-list treating as application/x-moz-file");
+    MOZ_CLIPBOARD_LOG(
+        "    has text/uri-list treating as application/x-moz-file");
     return true;
   }
   return false;
@@ -972,8 +989,9 @@ nsClipboard::HasNativeClipboardDataMatchingFlavors(
   MOZ_DIAGNOSTIC_ASSERT(
       nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
 
-  LOGCLIP("nsClipboard::HasNativeClipboardDataMatchingFlavors (%s)\n",
-          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::HasNativeClipboardDataMatchingFlavors (%s)\n",
+      aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
 
   if (!mContext) {
     return Err(NS_ERROR_FAILURE);
@@ -981,25 +999,25 @@ nsClipboard::HasNativeClipboardDataMatchingFlavors(
 
   auto targets = mContext->GetTargets(aWhichClipboard);
   if (!targets) {
-    LOGCLIP("    no targes at clipboard (null)\n");
+    MOZ_CLIPBOARD_LOG("    no targes at clipboard (null)\n");
     return false;
   }
 
 #ifdef MOZ_LOGGING
-  if (LOGCLIP_ENABLED()) {
-    LOGCLIP("    Asking for content:\n");
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    MOZ_CLIPBOARD_LOG("    Asking for content:\n");
     for (auto& flavor : aFlavorList) {
-      LOGCLIP("        MIME %s\n", flavor.get());
+      MOZ_CLIPBOARD_LOG("        MIME %s\n", flavor.get());
     }
-    LOGCLIP("    Clipboard content (target nums %zu):\n",
-            targets.AsSpan().Length());
+    MOZ_CLIPBOARD_LOG("    Clipboard content (target nums %zu):\n",
+                      targets.AsSpan().Length());
     for (const auto& target : targets.AsSpan()) {
       GUniquePtr<gchar> atom_name(gdk_atom_name(target));
       if (!atom_name) {
-        LOGCLIP("        failed to get MIME\n");
+        MOZ_CLIPBOARD_LOG("        failed to get MIME\n");
         continue;
       }
-      LOGCLIP("        MIME %s\n", atom_name.get());
+      MOZ_CLIPBOARD_LOG("        MIME %s\n", atom_name.get());
     }
   }
 #endif
@@ -1011,7 +1029,7 @@ nsClipboard::HasNativeClipboardDataMatchingFlavors(
     if (flavor.EqualsLiteral(kTextMime) &&
         gtk_targets_include_text(targets.AsSpan().data(),
                                  targets.AsSpan().Length())) {
-      LOGCLIP("    has kTextMime\n");
+      MOZ_CLIPBOARD_LOG("    has kTextMime\n");
       return true;
     }
     for (const auto& target : targets.AsSpan()) {
@@ -1021,7 +1039,7 @@ nsClipboard::HasNativeClipboardDataMatchingFlavors(
     }
   }
 
-  LOGCLIP("    no targes at clipboard (bad match)\n");
+  MOZ_CLIPBOARD_LOG("    no targes at clipboard (bad match)\n");
   return false;
 }
 
@@ -1030,10 +1048,10 @@ struct TragetCallbackHandler {
                         nsBaseClipboard::HasMatchingFlavorsCallback&& aCallback)
       : mAcceptedFlavorList(aAcceptedFlavorList.Clone()),
         mCallback(std::move(aCallback)) {
-    LOGCLIP("TragetCallbackHandler(%p) created", this);
+    MOZ_CLIPBOARD_LOG("TragetCallbackHandler(%p) created", this);
   }
   ~TragetCallbackHandler() {
-    LOGCLIP("TragetCallbackHandler(%p) deleted", this);
+    MOZ_CLIPBOARD_LOG("TragetCallbackHandler(%p) deleted", this);
   }
   nsTArray<nsCString> mAcceptedFlavorList;
   nsBaseClipboard::HasMatchingFlavorsCallback mCallback;
@@ -1045,15 +1063,17 @@ void nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors(
   MOZ_DIAGNOSTIC_ASSERT(
       nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
 
-  LOGCLIP("nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors (%s)",
-          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors (%s)",
+      aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
 
   gtk_clipboard_request_contents(
       gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
       gdk_atom_intern("TARGETS", FALSE),
       [](GtkClipboard* aClipboard, GtkSelectionData* aSelection,
          gpointer aData) -> void {
-        LOGCLIP("gtk_clipboard_request_contents async handler (%p)", aData);
+        MOZ_CLIPBOARD_LOG("gtk_clipboard_request_contents async handler (%p)",
+                          aData);
         UniquePtr<TragetCallbackHandler> handler(
             static_cast<TragetCallbackHandler*>(aData));
 
@@ -1061,15 +1081,30 @@ void nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors(
         gint targetsNum = 0;
         if (gtk_selection_data_get_length(aSelection) > 0) {
           gtk_selection_data_get_targets(aSelection, &targets, &targetsNum);
+
+#ifdef MOZ_LOGGING
+          if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+            MOZ_CLIPBOARD_LOG("  Clipboard content (target nums %d):\n",
+                              targetsNum);
+            for (int i = 0; i < targetsNum; i++) {
+              GUniquePtr<gchar> atom_name(gdk_atom_name(targets[i]));
+              if (!atom_name) {
+                MOZ_CLIPBOARD_LOG("    failed to get MIME\n");
+                continue;
+              }
+              MOZ_CLIPBOARD_LOG("    MIME %s\n", atom_name.get());
+            }
+          }
+#endif
         }
         nsTArray<nsCString> results;
         if (targetsNum) {
           for (auto& flavor : handler->mAcceptedFlavorList) {
-            LOGCLIP("  looking for %s", flavor.get());
+            MOZ_CLIPBOARD_LOG("  looking for %s", flavor.get());
             if (flavor.EqualsLiteral(kTextMime) &&
                 gtk_targets_include_text(targets, targetsNum)) {
               results.AppendElement(flavor);
-              LOGCLIP("    has kTextMime\n");
+              MOZ_CLIPBOARD_LOG("    has kTextMime\n");
               continue;
             }
             for (int i = 0; i < targetsNum; i++) {
@@ -1113,14 +1148,16 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
   else
     return;  // THAT AIN'T NO CLIPBOARD I EVER HEARD OF
 
-  LOGCLIP("nsClipboard::SelectionGetEvent (%s)\n",
-          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::SelectionGetEvent (%s)\n",
+      whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
 
   nsCOMPtr<nsITransferable> trans = GetTransferable(whichClipboard);
   if (!trans) {
     // We have nothing to serve
-    LOGCLIP("nsClipboard::SelectionGetEvent() - %s clipboard is empty!\n",
-            whichClipboard == kSelectionClipboard ? "Primary" : "Clipboard");
+    MOZ_CLIPBOARD_LOG(
+        "nsClipboard::SelectionGetEvent() - %s clipboard is empty!\n",
+        whichClipboard == kSelectionClipboard ? "Primary" : "Clipboard");
     return;
   }
 
@@ -1128,18 +1165,18 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
   nsCOMPtr<nsISupports> item;
 
   GdkAtom selectionTarget = gtk_selection_data_get_target(aSelectionData);
-  LOGCLIP("  selection target %s\n",
-          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+  MOZ_CLIPBOARD_LOG("  selection target %s\n",
+                    GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
 
   // Check to see if the selection data is some text type.
   if (gtk_targets_include_text(&selectionTarget, 1)) {
-    LOGCLIP("  providing text/plain data\n");
+    MOZ_CLIPBOARD_LOG("  providing text/plain data\n");
     // Try to convert our internal type into a text string.  Get
     // the transferable for this clipboard and try to get the
     // text/plain type for it.
     rv = trans->GetTransferData("text/plain", getter_AddRefs(item));
     if (NS_FAILED(rv) || !item) {
-      LOGCLIP("  GetTransferData() failed to get text/plain!\n");
+      MOZ_CLIPBOARD_LOG("  GetTransferData() failed to get text/plain!\n");
       return;
     }
 
@@ -1151,9 +1188,9 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
     wideString->GetData(ucs2string);
     NS_ConvertUTF16toUTF8 utf8string(ucs2string);
 
-    LOGCLIP("  sent %zd bytes of utf-8 data\n", utf8string.Length());
+    MOZ_CLIPBOARD_LOG("  sent %zd bytes of utf-8 data\n", utf8string.Length());
     if (selectionTarget == gdk_atom_intern("text/plain;charset=utf-8", FALSE)) {
-      LOGCLIP(
+      MOZ_CLIPBOARD_LOG(
           "  using gtk_selection_data_set for 'text/plain;charset=utf-8'\n");
       // Bypass gtk_selection_data_set_text, which will convert \n to \r\n
       // in some versions of GTK.
@@ -1169,7 +1206,7 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
 
   // Check to see if the selection data is an image type
   if (gtk_targets_include_image(&selectionTarget, 1, TRUE)) {
-    LOGCLIP("  providing image data\n");
+    MOZ_CLIPBOARD_LOG("  providing image data\n");
     // Look through our transfer data for the image
     static const char* const imageMimeTypes[] = {kNativeImageMime,
                                                  kPNGImageMime, kJPEGImageMime,
@@ -1179,47 +1216,50 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
     for (uint32_t i = 0; i < ArrayLength(imageMimeTypes); i++) {
       rv = trans->GetTransferData(imageMimeTypes[i], getter_AddRefs(imageItem));
       if (NS_FAILED(rv)) {
-        LOGCLIP("    %s is missing at GetTransferData()\n", imageMimeTypes[i]);
+        MOZ_CLIPBOARD_LOG("    %s is missing at GetTransferData()\n",
+                          imageMimeTypes[i]);
         continue;
       }
 
       image = do_QueryInterface(imageItem);
       if (image) {
-        LOGCLIP("    %s is available at GetTransferData()\n",
-                imageMimeTypes[i]);
+        MOZ_CLIPBOARD_LOG("    %s is available at GetTransferData()\n",
+                          imageMimeTypes[i]);
         break;
       }
     }
 
     if (!image) {  // Not getting an image for an image mime type!?
-      LOGCLIP("    Failed to get any image mime from GetTransferData()!\n");
+      MOZ_CLIPBOARD_LOG(
+          "    Failed to get any image mime from GetTransferData()!\n");
       return;
     }
 
     RefPtr<GdkPixbuf> pixbuf = nsImageToPixbuf::ImageToPixbuf(image);
     if (!pixbuf) {
-      LOGCLIP("    nsImageToPixbuf::ImageToPixbuf() failed!\n");
+      MOZ_CLIPBOARD_LOG("    nsImageToPixbuf::ImageToPixbuf() failed!\n");
       return;
     }
 
-    LOGCLIP("    Setting pixbuf image data as %s\n",
-            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    MOZ_CLIPBOARD_LOG("    Setting pixbuf image data as %s\n",
+                      GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
     gtk_selection_data_set_pixbuf(aSelectionData, pixbuf);
     return;
   }
 
   if (selectionTarget == gdk_atom_intern(kHTMLMime, FALSE)) {
-    LOGCLIP("  providing %s data\n", kHTMLMime);
+    MOZ_CLIPBOARD_LOG("  providing %s data\n", kHTMLMime);
     rv = trans->GetTransferData(kHTMLMime, getter_AddRefs(item));
     if (NS_FAILED(rv) || !item) {
-      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kHTMLMime);
+      MOZ_CLIPBOARD_LOG("  failed to get %s data by GetTransferData()!\n",
+                        kHTMLMime);
       return;
     }
 
     nsCOMPtr<nsISupportsString> wideString;
     wideString = do_QueryInterface(item);
     if (!wideString) {
-      LOGCLIP("  failed to get wideString interface!");
+      MOZ_CLIPBOARD_LOG("  failed to get wideString interface!");
       return;
     }
 
@@ -1231,8 +1271,8 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
     html.AppendLiteral(kHTMLMarkupPrefix);
     AppendUTF16toUTF8(ucs2string, html);
 
-    LOGCLIP("  Setting %zd bytes of %s data\n", html.Length(),
-            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    MOZ_CLIPBOARD_LOG("  Setting %zd bytes of %s data\n", html.Length(),
+                      GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
     gtk_selection_data_set(aSelectionData, selectionTarget, 8,
                            (const guchar*)html.get(), html.Length());
     return;
@@ -1240,53 +1280,54 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
 
   // We put kFileMime onto the clipboard as kURIListMime.
   if (selectionTarget == gdk_atom_intern(kURIListMime, FALSE)) {
-    LOGCLIP("  providing %s data\n", kURIListMime);
+    MOZ_CLIPBOARD_LOG("  providing %s data\n", kURIListMime);
     rv = trans->GetTransferData(kFileMime, getter_AddRefs(item));
     if (NS_FAILED(rv) || !item) {
-      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kFileMime);
+      MOZ_CLIPBOARD_LOG("  failed to get %s data by GetTransferData()!\n",
+                        kFileMime);
       return;
     }
 
     nsCOMPtr<nsIFile> file = do_QueryInterface(item);
     if (!file) {
-      LOGCLIP("  failed to get nsIFile interface!");
+      MOZ_CLIPBOARD_LOG("  failed to get nsIFile interface!");
       return;
     }
 
     nsCOMPtr<nsIURI> fileURI;
     rv = NS_NewFileURI(getter_AddRefs(fileURI), file);
     if (NS_FAILED(rv)) {
-      LOGCLIP("  failed to get fileURI\n");
+      MOZ_CLIPBOARD_LOG("  failed to get fileURI\n");
       return;
     }
 
     nsAutoCString uri;
     if (NS_FAILED(fileURI->GetSpec(uri))) {
-      LOGCLIP("  failed to get fileURI spec\n");
+      MOZ_CLIPBOARD_LOG("  failed to get fileURI spec\n");
       return;
     }
 
-    LOGCLIP("  Setting %zd bytes of data\n", uri.Length());
+    MOZ_CLIPBOARD_LOG("  Setting %zd bytes of data\n", uri.Length());
     gtk_selection_data_set(aSelectionData, selectionTarget, 8,
                            (const guchar*)uri.get(), uri.Length());
     return;
   }
 
-  LOGCLIP("  Try if we have anything at GetTransferData() for %s\n",
-          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+  MOZ_CLIPBOARD_LOG("  Try if we have anything at GetTransferData() for %s\n",
+                    GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
 
   // Try to match up the selection data target to something our
   // transferable provides.
   GUniquePtr<gchar> target_name(gdk_atom_name(selectionTarget));
   if (!target_name) {
-    LOGCLIP("  Failed to get target name!\n");
+    MOZ_CLIPBOARD_LOG("  Failed to get target name!\n");
     return;
   }
 
   rv = trans->GetTransferData(target_name.get(), getter_AddRefs(item));
   // nothing found?
   if (NS_FAILED(rv) || !item) {
-    LOGCLIP("  Failed to get anything from GetTransferData()!\n");
+    MOZ_CLIPBOARD_LOG("  Failed to get anything from GetTransferData()!\n");
     return;
   }
 
@@ -1295,12 +1336,12 @@ void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
   nsPrimitiveHelpers::CreateDataFromPrimitive(
       nsDependentCString(target_name.get()), item, &primitive_data, &dataLen);
   if (!primitive_data) {
-    LOGCLIP("  Failed to get primitive data!\n");
+    MOZ_CLIPBOARD_LOG("  Failed to get primitive data!\n");
     return;
   }
 
-  LOGCLIP("  Setting %s as a primitive data type, %d bytes\n",
-          target_name.get(), dataLen);
+  MOZ_CLIPBOARD_LOG("  Setting %s as a primitive data type, %d bytes\n",
+                    target_name.get(), dataLen);
   gtk_selection_data_set(aSelectionData, selectionTarget,
                          8, /* 8 bits in a unit */
                          (const guchar*)primitive_data, dataLen);
@@ -1320,8 +1361,9 @@ void nsClipboard::SelectionClearEvent(GtkClipboard* aGtkClipboard) {
   if (whichClipboard < 0) {
     return;
   }
-  LOGCLIP("nsClipboard::SelectionClearEvent (%s)\n",
-          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::SelectionClearEvent (%s)\n",
+      whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
   ClearCachedTargets(whichClipboard);
   ClearTransferable(whichClipboard);
   ClearClipboardCache(whichClipboard);
@@ -1333,8 +1375,9 @@ void nsClipboard::OwnerChangedEvent(GtkClipboard* aGtkClipboard,
   if (whichClipboard < 0) {
     return;
   }
-  LOGCLIP("nsClipboard::OwnerChangedEvent (%s)\n",
-          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  MOZ_CLIPBOARD_LOG(
+      "nsClipboard::OwnerChangedEvent (%s)\n",
+      whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
   GtkWidget* gtkWidget = [aEvent]() -> GtkWidget* {
     if (!aEvent->owner) {
       return nullptr;
@@ -1360,13 +1403,13 @@ void nsClipboard::OwnerChangedEvent(GtkClipboard* aGtkClipboard,
 void clipboard_get_cb(GtkClipboard* aGtkClipboard,
                       GtkSelectionData* aSelectionData, guint info,
                       gpointer user_data) {
-  LOGCLIP("clipboard_get_cb() callback\n");
+  MOZ_CLIPBOARD_LOG("clipboard_get_cb() callback\n");
   nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
   clipboard->SelectionGetEvent(aGtkClipboard, aSelectionData);
 }
 
 void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data) {
-  LOGCLIP("clipboard_clear_cb() callback\n");
+  MOZ_CLIPBOARD_LOG("clipboard_clear_cb() callback\n");
   nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
   clipboard->SelectionClearEvent(aGtkClipboard);
 }
@@ -1374,7 +1417,7 @@ void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data) {
 void clipboard_owner_change_cb(GtkClipboard* aGtkClipboard,
                                GdkEventOwnerChange* aEvent,
                                gpointer aUserData) {
-  LOGCLIP("clipboard_owner_change_cb() callback\n");
+  MOZ_CLIPBOARD_LOG("clipboard_owner_change_cb() callback\n");
   nsClipboard* clipboard = static_cast<nsClipboard*>(aUserData);
   clipboard->OwnerChangedEvent(aGtkClipboard, aEvent);
 }
diff --git a/widget/gtk/nsClipboard.h b/widget/gtk/nsClipboard.h
index 0ddbb59827..358136ae4e 100644
--- a/widget/gtk/nsClipboard.h
+++ b/widget/gtk/nsClipboard.h
@@ -17,20 +17,6 @@
 #include "GUniquePtr.h"
 #include <gtk/gtk.h>
 
-#ifdef MOZ_LOGGING
-#  include "mozilla/Logging.h"
-#  include "nsTArray.h"
-#  include "Units.h"
-extern mozilla::LazyLogModule gClipboardLog;
-#  define LOGCLIP(...) \
-    MOZ_LOG(gClipboardLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
-#  define LOGCLIP_ENABLED() \
-    MOZ_LOG_TEST(gClipboardLog, mozilla::LogLevel::Debug)
-#else
-#  define LOGCLIP(...)
-#  define LOGCLIP_ENABLED() false
-#endif /* MOZ_LOGGING */
-
 class ClipboardTargets {
   friend class ClipboardData;
 
diff --git a/widget/gtk/nsClipboardWayland.cpp b/widget/gtk/nsClipboardWayland.cpp
index d179f242dd..316fcf90b6 100644
--- a/widget/gtk/nsClipboardWayland.cpp
+++ b/widget/gtk/nsClipboardWayland.cpp
@@ -22,7 +22,7 @@ nsRetrievalContextWayland::nsRetrievalContextWayland() = default;
 
 ClipboardTargets nsRetrievalContextWayland::GetTargetsImpl(
     int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContextWayland::GetTargetsImpl()\n");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContextWayland::GetTargetsImpl()\n");
 
   return WaitForClipboardData(ClipboardDataType::Targets, aWhichClipboard)
       .ExtractTargets();
@@ -30,7 +30,8 @@ ClipboardTargets nsRetrievalContextWayland::GetTargetsImpl(
 
 ClipboardData nsRetrievalContextWayland::GetClipboardData(
     const char* aMimeType, int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContextWayland::GetClipboardData() mime %s\n", aMimeType);
+  MOZ_CLIPBOARD_LOG("nsRetrievalContextWayland::GetClipboardData() mime %s\n",
+                    aMimeType);
 
   return WaitForClipboardData(ClipboardDataType::Data, aWhichClipboard,
                               aMimeType);
@@ -40,8 +41,9 @@ GUniquePtr<char> nsRetrievalContextWayland::GetClipboardText(
     int32_t aWhichClipboard) {
   GdkAtom selection = GetSelectionAtom(aWhichClipboard);
 
-  LOGCLIP("nsRetrievalContextWayland::GetClipboardText(), clipboard %s\n",
-          (selection == GDK_SELECTION_PRIMARY) ? "Primary" : "Selection");
+  MOZ_CLIPBOARD_LOG(
+      "nsRetrievalContextWayland::GetClipboardText(), clipboard %s\n",
+      (selection == GDK_SELECTION_PRIMARY) ? "Primary" : "Selection");
 
   return WaitForClipboardData(ClipboardDataType::Text, aWhichClipboard)
       .ExtractText();
@@ -50,8 +52,8 @@ GUniquePtr<char> nsRetrievalContextWayland::GetClipboardText(
 ClipboardData nsRetrievalContextWayland::WaitForClipboardData(
     ClipboardDataType aDataType, int32_t aWhichClipboard,
     const char* aMimeType) {
-  LOGCLIP("nsRetrievalContextWayland::WaitForClipboardData, MIME %s\n",
-          aMimeType);
+  MOZ_CLIPBOARD_LOG(
+      "nsRetrievalContextWayland::WaitForClipboardData, MIME %s\n", aMimeType);
 
   AsyncGtkClipboardRequest request(aDataType, aWhichClipboard, aMimeType);
   int iteration = 1;
@@ -62,12 +64,13 @@ ClipboardData nsRetrievalContextWayland::WaitForClipboardData(
       /* sleep for 10 ms/iteration */
       PR_Sleep(PR_MillisecondsToInterval(10));
       if (PR_Now() - entryTime > kClipboardTimeout) {
-        LOGCLIP("  failed to get async clipboard data in time limit\n");
+        MOZ_CLIPBOARD_LOG(
+            "  failed to get async clipboard data in time limit\n");
         break;
       }
     }
-    LOGCLIP("doing iteration %d msec %ld ...\n", (iteration - 1),
-            (long)((PR_Now() - entryTime) / 1000));
+    MOZ_CLIPBOARD_LOG("doing iteration %d msec %ld ...\n", (iteration - 1),
+                      (long)((PR_Now() - entryTime) / 1000));
     gtk_main_iteration();
   }
 
diff --git a/widget/gtk/nsClipboardX11.cpp b/widget/gtk/nsClipboardX11.cpp
index db12d1e69c..2693622922 100644
--- a/widget/gtk/nsClipboardX11.cpp
+++ b/widget/gtk/nsClipboardX11.cpp
@@ -138,25 +138,27 @@ ClipboardData nsRetrievalContextX11::WaitForClipboardData(
              (poll_result == -1 && errno == EINTR));
   }
 
-  LOGCLIP("exceeded clipboard timeout");
+  MOZ_CLIPBOARD_LOG("exceeded clipboard timeout");
   return {};
 }
 
 ClipboardTargets nsRetrievalContextX11::GetTargetsImpl(
     int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContextX11::GetTargetsImpl(%s)\n",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContextX11::GetTargetsImpl(%s)\n",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
   return WaitForClipboardData(ClipboardDataType::Targets, aWhichClipboard)
       .ExtractTargets();
 }
 
 ClipboardData nsRetrievalContextX11::GetClipboardData(const char* aMimeType,
                                                       int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContextX11::GetClipboardData(%s) MIME %s\n",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard",
-          aMimeType);
+  MOZ_CLIPBOARD_LOG("nsRetrievalContextX11::GetClipboardData(%s) MIME %s\n",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard",
+                    aMimeType);
 
   return WaitForClipboardData(ClipboardDataType::Data, aWhichClipboard,
                               aMimeType);
@@ -164,9 +166,10 @@ ClipboardData nsRetrievalContextX11::GetClipboardData(const char* aMimeType,
 
 GUniquePtr<char> nsRetrievalContextX11::GetClipboardText(
     int32_t aWhichClipboard) {
-  LOGCLIP("nsRetrievalContextX11::GetClipboardText(%s)\n",
-          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
-                                                              : "clipboard");
+  MOZ_CLIPBOARD_LOG("nsRetrievalContextX11::GetClipboardText(%s)\n",
+                    aWhichClipboard == nsClipboard::kSelectionClipboard
+                        ? "primary"
+                        : "clipboard");
 
   return WaitForClipboardData(ClipboardDataType::Text, aWhichClipboard)
       .ExtractText();
diff --git a/widget/gtk/nsDragService.cpp b/widget/gtk/nsDragService.cpp
index 6cabfbbe2e..c3a3136013 100644
--- a/widget/gtk/nsDragService.cpp
+++ b/widget/gtk/nsDragService.cpp
@@ -1750,7 +1750,7 @@ nsresult nsDragService::CreateTempFile(nsITransferable* aItem,
   }
 
   // create and open channel for source uri
-  nsCOMPtr<nsIPrincipal> principal = aItem->GetRequestingPrincipal();
+  nsCOMPtr<nsIPrincipal> principal = aItem->GetDataPrincipal();
   nsContentPolicyType contentPolicyType = aItem->GetContentPolicyType();
   nsCOMPtr<nsICookieJarSettings> cookieJarSettings =
       aItem->GetCookieJarSettings();
diff --git a/widget/gtk/nsLookAndFeel.cpp b/widget/gtk/nsLookAndFeel.cpp
index 8702c154d6..bfd3f1b6f4 100644
--- a/widget/gtk/nsLookAndFeel.cpp
+++ b/widget/gtk/nsLookAndFeel.cpp
@@ -904,8 +904,7 @@ nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
       break;
     }
     case IntID::MenusCanOverlapOSBar:
-      // we want XUL popups to be able to overlap the task bar.
-      aResult = 1;
+      aResult = 0;
       break;
     case IntID::SkipNavigatingDisabledMenuItem:
       aResult = 1;
@@ -1975,10 +1974,7 @@ void nsLookAndFeel::PerThemeData::Init() {
     mTitlebar = GetColorPair(style, GTK_STATE_FLAG_NORMAL);
     mTitlebarInactive = GetColorPair(style, GTK_STATE_FLAG_BACKDROP);
     mTitlebarRadius = IsSolidCSDStyleUsed() ? 0 : GetBorderRadius(style);
-    // Get titlebar spacing, a default one is 6 pixels (gtk/gtkheaderbar.c)
-    mTitlebarButtonSpacing = 6;
-    g_object_get(GetWidget(MOZ_GTK_HEADER_BAR), "spacing",
-                 &mTitlebarButtonSpacing, nullptr);
+    mTitlebarButtonSpacing = moz_gtk_get_titlebar_button_spacing();
   }
 
   // We special-case the header bar color in Adwaita, Yaru and Breeze to be the
diff --git a/widget/gtk/nsNativeThemeGTK.cpp b/widget/gtk/nsNativeThemeGTK.cpp
index 78d4e925fe..5c858d2313 100644
--- a/widget/gtk/nsNativeThemeGTK.cpp
+++ b/widget/gtk/nsNativeThemeGTK.cpp
@@ -195,14 +195,6 @@ bool nsNativeThemeGTK::GetGtkWidgetAndState(StyleAppearance aAppearance,
         aAppearance == StyleAppearance::Menulist ||
         aAppearance == StyleAppearance::MenulistButton) {
       aState->active &= aState->inHover;
-    } else if (aAppearance == StyleAppearance::Treetwisty ||
-               aAppearance == StyleAppearance::Treetwistyopen) {
-      if (nsTreeBodyFrame* treeBodyFrame = do_QueryFrame(aFrame)) {
-        const mozilla::AtomArray& atoms =
-            treeBodyFrame->GetPropertyArrayForCurrentDrawingItem();
-        aState->selected = atoms.Contains(nsGkAtoms::selected);
-        aState->inHover = atoms.Contains(nsGkAtoms::hover);
-      }
     }
 
     if (IsFrameContentNodeInNamespace(aFrame, kNameSpaceID_XUL)) {
@@ -292,6 +284,7 @@ bool nsNativeThemeGTK::GetGtkWidgetAndState(StyleAppearance aAppearance,
       break;
     }
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
       aGtkWidgetType = MOZ_GTK_ENTRY;
       break;
@@ -299,17 +292,8 @@ bool nsNativeThemeGTK::GetGtkWidgetAndState(StyleAppearance aAppearance,
       aGtkWidgetType = MOZ_GTK_TEXT_VIEW;
       break;
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
       aGtkWidgetType = MOZ_GTK_TREEVIEW;
       break;
-    case StyleAppearance::Treetwisty:
-      aGtkWidgetType = MOZ_GTK_TREEVIEW_EXPANDER;
-      if (aWidgetFlags) *aWidgetFlags = GTK_EXPANDER_COLLAPSED;
-      break;
-    case StyleAppearance::Treetwistyopen:
-      aGtkWidgetType = MOZ_GTK_TREEVIEW_EXPANDER;
-      if (aWidgetFlags) *aWidgetFlags = GTK_EXPANDER_EXPANDED;
-      break;
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Menulist:
       aGtkWidgetType = MOZ_GTK_DROPDOWN;
@@ -1091,6 +1075,7 @@ LayoutDeviceIntSize nsNativeThemeGTK::GetMinimumWidgetSize(
       result.height += border.TopBottom();
     } break;
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield: {
       gint contentHeight = 0;
       gint borderPaddingHeight = 0;
@@ -1135,12 +1120,6 @@ LayoutDeviceIntSize nsNativeThemeGTK::GetMinimumWidgetSize(
       result.width = 14;
       result.height = 13;
       break;
-    case StyleAppearance::Treetwisty:
-    case StyleAppearance::Treetwistyopen: {
-      gint expander_size;
-      moz_gtk_get_treeview_expander_size(&expander_size);
-      result.width = result.height = expander_size;
-    } break;
     default:
       break;
   }
@@ -1243,12 +1222,6 @@ nsNativeThemeGTK::ThemeSupportsWidget(nsPresContext* aPresContext,
     case StyleAppearance::ButtonArrowNext:
     case StyleAppearance::ButtonArrowPrevious:
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
-      // case StyleAppearance::Treeitem:
-    case StyleAppearance::Treetwisty:
-      // case StyleAppearance::Treeline:
-      // case StyleAppearance::Treeheader:
-    case StyleAppearance::Treetwistyopen:
     case StyleAppearance::ProgressBar:
     case StyleAppearance::Progresschunk:
     case StyleAppearance::Tab:
@@ -1262,6 +1235,7 @@ nsNativeThemeGTK::ThemeSupportsWidget(nsPresContext* aPresContext,
     case StyleAppearance::SpinnerDownbutton:
     case StyleAppearance::SpinnerTextfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Range:
@@ -1315,6 +1289,7 @@ bool nsNativeThemeGTK::ThemeDrawsFocusForWidget(nsIFrame* aFrame,
     case StyleAppearance::Textarea:
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
       return true;
     default:
       return false;
diff --git a/widget/gtk/nsWaylandDisplay.cpp b/widget/gtk/nsWaylandDisplay.cpp
index 1ea87b3bc5..c63c8f6564 100644
--- a/widget/gtk/nsWaylandDisplay.cpp
+++ b/widget/gtk/nsWaylandDisplay.cpp
@@ -28,7 +28,6 @@ void WaylandDisplayRelease() {
   MOZ_RELEASE_ASSERT(NS_IsMainThread(),
                      "WaylandDisplay can be released in main thread only!");
   if (!gWaylandDisplay) {
-    NS_WARNING("WaylandDisplayRelease(): Wayland display is missing!");
     return;
   }
   delete gWaylandDisplay;
@@ -151,7 +150,6 @@ static void global_registry_handler(void* data, wl_registry* registry,
             registry, id, &xdg_dbus_annotation_manager_v1_interface, 1);
     display->SetXdgDbusAnnotationManager(annotationManager);
   } else if (iface.EqualsLiteral("wl_seat")) {
-    // Install keyboard handlers for main thread only
     auto* seat =
         WaylandRegistryBind<wl_seat>(registry, id, &wl_seat_interface, 1);
     KeymapWrapper::SetSeat(seat, id);
@@ -173,7 +171,7 @@ static void global_registry_remover(void* data, wl_registry* registry,
 static const struct wl_registry_listener registry_listener = {
     global_registry_handler, global_registry_remover};
 
-nsWaylandDisplay::~nsWaylandDisplay() {}
+nsWaylandDisplay::~nsWaylandDisplay() = default;
 
 static void WlLogHandler(const char* format, va_list args) {
   char error[1000];
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 0a78d0c8ec..2971497969 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -389,8 +389,7 @@ static void GtkWindowSetTransientFor(GtkWindow* aWindow, GtkWindow* aParent) {
   }
 
 nsWindow::nsWindow()
-    : mTitlebarRectMutex("nsWindow::mTitlebarRectMutex"),
-      mWindowVisibilityMutex("nsWindow::mWindowVisibilityMutex"),
+    : mWindowVisibilityMutex("nsWindow::mWindowVisibilityMutex"),
       mIsMapped(false),
       mIsDestroyed(false),
       mIsShown(false),
@@ -514,10 +513,6 @@ void nsWindow::MaybeDispatchResized() {
                           << mBounds << " size state " << mSizeMode;
     }
 
-    if (IsTopLevelWindowType()) {
-      UpdateTopLevelOpaqueRegion();
-    }
-
     // Notify the GtkCompositorWidget of a ClientSizeChange
     if (mCompositorWidgetDelegate) {
       mCompositorWidgetDelegate->NotifyClientSizeChanged(GetClientSize());
@@ -591,6 +586,7 @@ void nsWindow::Destroy() {
     mWaylandVsyncSource = nullptr;
   }
   mWaylandVsyncDispatcher = nullptr;
+  UnlockNativePointer();
 #endif
 
   // dragService will be null after shutdown of the service manager.
@@ -3216,9 +3212,7 @@ LayoutDeviceIntRect nsWindow::GetScreenBounds() {
   return rect;
 }
 
-LayoutDeviceIntSize nsWindow::GetClientSize() {
-  return LayoutDeviceIntSize(mBounds.width, mBounds.height);
-}
+LayoutDeviceIntSize nsWindow::GetClientSize() { return mBounds.Size(); }
 
 LayoutDeviceIntRect nsWindow::GetClientBounds() {
   // GetBounds returns a rect whose top left represents the top left of the
@@ -5379,8 +5373,6 @@ void nsWindow::OnWindowStateEvent(GtkWidget* aWidget,
     } else {
       ClearTransparencyBitmap();
     }
-  } else {
-    SetTitlebarRect();
   }
 }
 
@@ -5391,7 +5383,6 @@ void nsWindow::OnDPIChanged() {
     if (PresShell* presShell = mWidgetListener->GetPresShell()) {
       presShell->BackingScaleFactorChanged();
     }
-    mWidgetListener->UIResolutionChanged();
   }
   NotifyAPZOfDPIChange();
 }
@@ -6934,80 +6925,99 @@ LayoutDeviceIntCoord nsWindow::GetTitlebarRadius() {
   return GdkCoordToDevicePixels(cssCoord);
 }
 
+LayoutDeviceIntRegion nsWindow::GetOpaqueRegion() const {
+  AutoReadLock r(mOpaqueRegionLock);
+  return mOpaqueRegion;
+}
+
 // See subtract_corners_from_region() at gtk/gtkwindow.c
 // We need to subtract corners from toplevel window opaque region
 // to draw transparent corners of default Gtk titlebar.
 // Both implementations (cairo_region_t and wl_region) needs to be synced.
-static void SubtractTitlebarCorners(cairo_region_t* aRegion, int aX, int aY,
-                                    int aWindowWidth, int aWindowHeight,
-                                    int aTitlebarRadius) {
-  if (!aTitlebarRadius) {
-    return;
-  }
-  cairo_rectangle_int_t rect = {aX, aY, aTitlebarRadius, aTitlebarRadius};
-  cairo_region_subtract_rectangle(aRegion, &rect);
-  rect = {
-      aX + aWindowWidth - aTitlebarRadius,
-      aY,
-      aTitlebarRadius,
-      aTitlebarRadius,
-  };
-  cairo_region_subtract_rectangle(aRegion, &rect);
-  rect = {
-      aX,
-      aY + aWindowHeight - aTitlebarRadius,
-      aTitlebarRadius,
-      aTitlebarRadius,
-  };
-  cairo_region_subtract_rectangle(aRegion, &rect);
-  rect = {
-      aX + aWindowWidth - aTitlebarRadius,
-      aY + aWindowHeight - aTitlebarRadius,
-      aTitlebarRadius,
-      aTitlebarRadius,
-  };
-  cairo_region_subtract_rectangle(aRegion, &rect);
+static void SubtractTitlebarCorners(LayoutDeviceIntRegion& aRegion,
+                                    const LayoutDeviceIntRect& aRect,
+                                    LayoutDeviceIntCoord aRadius) {
+  if (!aRadius) {
+    return;
+  }
+  const LayoutDeviceIntSize size(aRadius, aRadius);
+  aRegion.SubOut(LayoutDeviceIntRect(aRect.TopLeft(), size));
+  aRegion.SubOut(LayoutDeviceIntRect(
+      aRect.TopRight() - LayoutDeviceIntPoint(aRadius, 0), size));
+  aRegion.SubOut(LayoutDeviceIntRect(
+      aRect.BottomLeft() - LayoutDeviceIntPoint(0, aRadius), size));
+  aRegion.SubOut(LayoutDeviceIntRect(
+      aRect.BottomRight() - LayoutDeviceIntPoint(aRadius, aRadius), size));
+}
+
+void nsWindow::UpdateOpaqueRegion(const LayoutDeviceIntRegion& aRegion) {
+  LayoutDeviceIntRegion region = aRegion;
+  SubtractTitlebarCorners(region, LayoutDeviceIntRect({}, mBounds.Size()),
+                          GetTitlebarRadius());
+  {
+    AutoReadLock r(mOpaqueRegionLock);
+    if (mOpaqueRegion == region) {
+      return;
+    }
+  }
+  {
+    AutoWriteLock w(mOpaqueRegionLock);
+    mOpaqueRegion = region;
+  }
+  UpdateOpaqueRegionInternal();
 }
 
-void nsWindow::UpdateTopLevelOpaqueRegion() {
+void nsWindow::UpdateOpaqueRegionInternal() {
   if (!mCompositedScreen) {
     return;
   }
 
+  if (!IsTopLevelWindowType()) {
+    // We need to clear target buffer alpha values of popup windows as
+    // SW-WR paints with alpha blending (see Bug 1674473).
+    return;
+  }
+
   GdkWindow* window = GetToplevelGdkWindow();
   if (!window) {
     return;
   }
   MOZ_ASSERT(gdk_window_get_window_type(window) == GDK_WINDOW_TOPLEVEL);
 
-  int x = 0;
-  int y = 0;
-
-  gdk_window_get_position(mGdkWindow, &x, &y);
-
-  int width = DevicePixelsToGdkCoordRoundDown(mBounds.width);
-  int height = DevicePixelsToGdkCoordRoundDown(mBounds.height);
-
-  cairo_region_t* region = cairo_region_create();
-  cairo_rectangle_int_t rect = {x, y, width, height};
-  cairo_region_union_rectangle(region, &rect);
-
-  // TODO: We actually could get a proper opaque region from layout, see
-  // nsIWidget::UpdateOpaqueRegion. This could simplify titlebar drawing.
-  int radius = DoDrawTilebarCorners() ? int(GetTitlebarRadius()) : 0;
-  SubtractTitlebarCorners(region, x, y, width, height, radius);
-
-  gdk_window_set_opaque_region(window, region);
-
-  cairo_region_destroy(region);
+  {
+    AutoReadLock lock(mOpaqueRegionLock);
+    cairo_region_t* region = nullptr;
+    if (!mOpaqueRegion.IsEmpty()) {
+      // NOTE(emilio): The opaque region is relative to our mContainer /
+      // mGdkWindow / inner window, but we're setting it on the top level
+      // GdkWindow / mShell.
+      //
+      // So we need to offset the rects by the position of mGdkWindow, in order
+      // for them to be in the right coordinate system.
+      GdkPoint offset{0, 0};
+      gdk_window_get_position(mGdkWindow, &offset.x, &offset.y);
+
+      region = cairo_region_create();
+
+      for (auto iter = mOpaqueRegion.RectIter(); !iter.Done(); iter.Next()) {
+        auto gdkRect = DevicePixelsToGdkRectRoundIn(iter.Get());
+        cairo_rectangle_int_t rect = {gdkRect.x + offset.x,
+                                      gdkRect.y + offset.y, gdkRect.width,
+                                      gdkRect.height};
+        cairo_region_union_rectangle(region, &rect);
+      }
+    }
+    gdk_window_set_opaque_region(window, region);
+    if (region) {
+      cairo_region_destroy(region);
+    }
+  }
 
 #ifdef MOZ_WAYLAND
   if (GdkIsWaylandDisplay()) {
-    moz_container_wayland_update_opaque_region(mContainer, radius);
+    moz_container_wayland_update_opaque_region(mContainer);
   }
 #endif
-
-  SetTitlebarRect();
 }
 
 bool nsWindow::IsChromeWindowTitlebar() {
@@ -7181,24 +7191,6 @@ nsresult nsWindow::UpdateTranslucentWindowAlphaInternal(const nsIntRect& aRect,
   return NS_OK;
 }
 
-#define TITLEBAR_HEIGHT 10
-
-void nsWindow::SetTitlebarRect() {
-  MutexAutoLock lock(mTitlebarRectMutex);
-
-  if (!mGdkWindow || !DoDrawTilebarCorners()) {
-    mTitlebarRect = LayoutDeviceIntRect();
-    return;
-  }
-  mTitlebarRect = LayoutDeviceIntRect(0, 0, mBounds.width,
-                                      GdkCeiledScaleFactor() * TITLEBAR_HEIGHT);
-}
-
-LayoutDeviceIntRect nsWindow::GetTitlebarRect() {
-  MutexAutoLock lock(mTitlebarRectMutex);
-  return mTitlebarRect;
-}
-
 void nsWindow::UpdateTitlebarTransparencyBitmap() {
   NS_ASSERTION(mTransparencyBitmapForTitlebar,
                "Transparency bitmap is already used to draw window shape");
@@ -8243,7 +8235,9 @@ static void toplevel_window_size_allocate_cb(GtkWidget* widget,
     return;
   }
 
-  window->UpdateTopLevelOpaqueRegion();
+  // NOTE(emilio): We need to do this here to override GTK's own opaque region
+  // setting (which would clobber ours).
+  window->UpdateOpaqueRegionInternal();
 }
 
 static gboolean delete_event_cb(GtkWidget* widget, GdkEventAny* event) {
@@ -9180,9 +9174,11 @@ void nsWindow::SetDrawsInTitlebar(bool aState) {
     } else {
       ClearTransparencyBitmap();
     }
-  } else {
-    SetTitlebarRect();
   }
+
+  // Recompute the input region (which should generally be null, but this is
+  // enough to work around bug 1844497, which is probably a gtk bug).
+  SetInputRegion(mInputRegion);
 }
 
 GtkWindow* nsWindow::GetCurrentTopmostWindow() const {
@@ -9249,6 +9245,16 @@ GdkRectangle nsWindow::DevicePixelsToGdkRectRoundOut(
   return {x, y, right - x, bottom - y};
 }
 
+GdkRectangle nsWindow::DevicePixelsToGdkRectRoundIn(
+    const LayoutDeviceIntRect& aRect) {
+  double scale = FractionalScaleFactor();
+  int x = ceil(aRect.x / scale);
+  int y = ceil(aRect.y / scale);
+  int right = floor((aRect.x + aRect.width) / scale);
+  int bottom = floor((aRect.y + aRect.height) / scale);
+  return {x, y, std::max(right - x, 0), std::max(bottom - y, 0)};
+}
+
 GdkRectangle nsWindow::DevicePixelsToGdkSizeRoundUp(
     const LayoutDeviceIntSize& aSize) {
   double scale = FractionalScaleFactor();
@@ -9843,9 +9849,7 @@ void nsWindow::LockNativePointer() {
     return;
   }
 
-  if (mLockedPointer || mRelativePointer) {
-    UnlockNativePointer();
-  }
+  UnlockNativePointer();
 
   mLockedPointer = zwp_pointer_constraints_v1_lock_pointer(
       pointerConstraints, surface, pointer, nullptr,
@@ -9869,9 +9873,6 @@ void nsWindow::LockNativePointer() {
 }
 
 void nsWindow::UnlockNativePointer() {
-  if (!GdkIsWaylandDisplay()) {
-    return;
-  }
   if (mRelativePointer) {
     zwp_relative_pointer_v1_destroy(mRelativePointer);
     mRelativePointer = nullptr;
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
index 25d68129d8..1dd1f1dce8 100644
--- a/widget/gtk/nsWindow.h
+++ b/widget/gtk/nsWindow.h
@@ -19,6 +19,7 @@
 #include "mozilla/RefPtr.h"
 #include "mozilla/TouchEvents.h"
 #include "mozilla/UniquePtr.h"
+#include "mozilla/RWLock.h"
 #include "mozilla/widget/WindowSurface.h"
 #include "mozilla/widget/WindowSurfaceProvider.h"
 #include "nsBaseWidget.h"
@@ -257,7 +258,9 @@ class nsWindow final : public nsBaseWidget {
 
   gint GetInputRegionMarginInGdkCoords();
 
-  void UpdateTopLevelOpaqueRegion();
+  void UpdateOpaqueRegionInternal();
+  void UpdateOpaqueRegion(const LayoutDeviceIntRegion&) override;
+  LayoutDeviceIntRegion GetOpaqueRegion() const;
 
   already_AddRefed<mozilla::gfx::DrawTarget> StartRemoteDrawingInRegion(
       const LayoutDeviceIntRegion& aInvalidRegion,
@@ -369,9 +372,7 @@ class nsWindow final : public nsBaseWidget {
 
   nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) override;
   void SetDrawsInTitlebar(bool aState);
-  void SetTitlebarRect();
   mozilla::LayoutDeviceIntCoord GetTitlebarRadius();
-  LayoutDeviceIntRect GetTitlebarRect();
   void UpdateWindowDraggingRegion(
       const LayoutDeviceIntRegion& aRegion) override;
 
@@ -389,6 +390,7 @@ class nsWindow final : public nsBaseWidget {
   GdkPoint DevicePixelsToGdkPointRoundDown(const LayoutDeviceIntPoint&);
   GdkRectangle DevicePixelsToGdkSizeRoundUp(const LayoutDeviceIntSize&);
   GdkRectangle DevicePixelsToGdkRectRoundOut(const LayoutDeviceIntRect&);
+  GdkRectangle DevicePixelsToGdkRectRoundIn(const LayoutDeviceIntRect&);
 
   // From GDK
   int GdkCoordToDevicePixels(gint);
@@ -631,9 +633,6 @@ class nsWindow final : public nsBaseWidget {
   // If true, draw our own window titlebar.
   bool mDrawInTitlebar = false;
 
-  mozilla::Mutex mTitlebarRectMutex;
-  LayoutDeviceIntRect mTitlebarRect MOZ_GUARDED_BY(mTitlebarRectMutex);
-
   // This mutex protect window visibility changes.
   mozilla::Mutex mWindowVisibilityMutex;
 
@@ -1018,6 +1017,8 @@ class nsWindow final : public nsBaseWidget {
   // Running in kiosk mode and requested to stay on specified monitor.
   // If monitor is removed minimize the window.
   mozilla::Maybe<int> mKioskMonitor;
+  LayoutDeviceIntRegion mOpaqueRegion MOZ_GUARDED_BY(mOpaqueRegionLock);
+  mutable mozilla::RWLock mOpaqueRegionLock{"nsWindow::mOpaqueRegion"};
 };
 
 #endif /* __nsWindow_h__ */
diff --git a/widget/headless/HeadlessLookAndFeelGTK.cpp b/widget/headless/HeadlessLookAndFeelGTK.cpp
index aa55bcc347..09938e1983 100644
--- a/widget/headless/HeadlessLookAndFeelGTK.cpp
+++ b/widget/headless/HeadlessLookAndFeelGTK.cpp
@@ -84,9 +84,6 @@ nsresult HeadlessLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
     case IntID::TreeScrollLinesMax:
       aResult = 3;
       break;
-    case IntID::TabFocusModel:
-      aResult = nsIContent::eTabFocus_textControlsMask;
-      break;
     case IntID::ChosenMenuItemsShouldBlink:
       aResult = 1;
       break;
diff --git a/widget/nsBaseClipboard.cpp b/widget/nsBaseClipboard.cpp
index 9ffc53b4c2..1eb2e8e9e0 100644
--- a/widget/nsBaseClipboard.cpp
+++ b/widget/nsBaseClipboard.cpp
@@ -7,7 +7,6 @@
 
 #include "ContentAnalysis.h"
 #include "mozilla/Components.h"
-#include "mozilla/contentanalysis/ContentAnalysisIPCTypes.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/CanonicalBrowsingContext.h"
 #include "mozilla/dom/Document.h"
@@ -19,14 +18,12 @@
 #include "mozilla/MoveOnlyFunction.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/Services.h"
-#include "mozilla/SpinEventLoopUntil.h"
 #include "mozilla/StaticPrefs_dom.h"
 #include "mozilla/StaticPrefs_widget.h"
 #include "nsContentUtils.h"
 #include "nsFocusManager.h"
 #include "nsIClipboardOwner.h"
 #include "nsIPromptService.h"
-#include "nsISupportsPrimitives.h"
 #include "nsError.h"
 #include "nsXPCOM.h"
 
@@ -38,6 +35,8 @@ using mozilla::dom::CanonicalBrowsingContext;
 using mozilla::dom::ClipboardCapabilities;
 using mozilla::dom::Document;
 
+mozilla::LazyLogModule gWidgetClipboardLog("WidgetClipboard");
+
 static const int32_t kGetAvailableFlavorsRetryCount = 5;
 
 namespace {
@@ -211,9 +210,11 @@ NS_IMPL_ISUPPORTS(nsBaseClipboard::AsyncSetClipboardData,
 
 nsBaseClipboard::AsyncSetClipboardData::AsyncSetClipboardData(
     int32_t aClipboardType, nsBaseClipboard* aClipboard,
+    mozilla::dom::WindowContext* aSettingWindowContext,
     nsIAsyncClipboardRequestCallback* aCallback)
     : mClipboardType(aClipboardType),
       mClipboard(aClipboard),
+      mWindowContext(aSettingWindowContext),
       mCallback(aCallback) {
   MOZ_ASSERT(mClipboard);
   MOZ_ASSERT(
@@ -247,7 +248,8 @@ nsBaseClipboard::AsyncSetClipboardData::SetData(nsITransferable* aTransferable,
 
   RefPtr<AsyncSetClipboardData> request =
       std::move(mClipboard->mPendingWriteRequests[mClipboardType]);
-  nsresult rv = mClipboard->SetData(aTransferable, aOwner, mClipboardType);
+  nsresult rv = mClipboard->SetData(aTransferable, aOwner, mClipboardType,
+                                    mWindowContext);
   MaybeNotifyCallback(rv);
 
   return rv;
@@ -292,7 +294,8 @@ void nsBaseClipboard::RejectPendingAsyncSetDataRequestIfAny(
 }
 
 NS_IMETHODIMP nsBaseClipboard::AsyncSetData(
-    int32_t aWhichClipboard, nsIAsyncClipboardRequestCallback* aCallback,
+    int32_t aWhichClipboard, mozilla::dom::WindowContext* aSettingWindowContext,
+    nsIAsyncClipboardRequestCallback* aCallback,
     nsIAsyncSetClipboardData** _retval) {
   MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
 
@@ -308,241 +311,13 @@ NS_IMETHODIMP nsBaseClipboard::AsyncSetData(
 
   // Create a new AsyncSetClipboardData.
   RefPtr<AsyncSetClipboardData> request =
-      mozilla::MakeRefPtr<AsyncSetClipboardData>(aWhichClipboard, this,
-                                                 aCallback);
+      mozilla::MakeRefPtr<AsyncSetClipboardData>(
+          aWhichClipboard, this, aSettingWindowContext, aCallback);
   mPendingWriteRequests[aWhichClipboard] = request;
   request.forget(_retval);
   return NS_OK;
 }
 
-namespace {
-class SafeContentAnalysisResultCallback final
-    : public nsIContentAnalysisCallback {
- public:
-  explicit SafeContentAnalysisResultCallback(
-      std::function<void(RefPtr<nsIContentAnalysisResult>&&)> aResolver)
-      : mResolver(std::move(aResolver)) {}
-  void Callback(RefPtr<nsIContentAnalysisResult>&& aResult) {
-    MOZ_ASSERT(mResolver, "Called SafeContentAnalysisResultCallback twice!");
-    if (auto resolver = std::move(mResolver)) {
-      resolver(std::move(aResult));
-    }
-  }
-
-  NS_IMETHODIMP ContentResult(nsIContentAnalysisResponse* aResponse) override {
-    using namespace mozilla::contentanalysis;
-    RefPtr<ContentAnalysisResult> result =
-        ContentAnalysisResult::FromContentAnalysisResponse(aResponse);
-    Callback(result);
-    return NS_OK;
-  }
-
-  NS_IMETHODIMP Error(nsresult aError) override {
-    using namespace mozilla::contentanalysis;
-    Callback(ContentAnalysisResult::FromNoResult(
-        NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR));
-    return NS_OK;
-  }
-
-  NS_DECL_THREADSAFE_ISUPPORTS
- private:
-  // Private destructor to force this to be allocated in a RefPtr, which is
-  // necessary for safe usage.
-  ~SafeContentAnalysisResultCallback() {
-    MOZ_ASSERT(!mResolver, "SafeContentAnalysisResultCallback never called!");
-  }
-  mozilla::MoveOnlyFunction<void(RefPtr<nsIContentAnalysisResult>&&)> mResolver;
-};
-NS_IMPL_ISUPPORTS(SafeContentAnalysisResultCallback,
-                  nsIContentAnalysisCallback);
-}  // namespace
-
-// Returning:
-//  - true means a content analysis request was fired
-//  - false means there is no text data in the transferable
-//  - NoContentAnalysisResult means there was an error
-static mozilla::Result<bool, mozilla::contentanalysis::NoContentAnalysisResult>
-CheckClipboardContentAnalysisAsText(
-    uint64_t aInnerWindowId, SafeContentAnalysisResultCallback* aResolver,
-    nsIURI* aDocumentURI, nsIContentAnalysis* aContentAnalysis,
-    nsITransferable* aTextTrans) {
-  using namespace mozilla::contentanalysis;
-
-  nsCOMPtr<nsISupports> transferData;
-  if (NS_FAILED(aTextTrans->GetTransferData(kTextMime,
-                                            getter_AddRefs(transferData)))) {
-    return false;
-  }
-  nsCOMPtr<nsISupportsString> textData = do_QueryInterface(transferData);
-  if (MOZ_UNLIKELY(!textData)) {
-    return false;
-  }
-  nsString text;
-  if (NS_FAILED(textData->GetData(text))) {
-    return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-  }
-  if (text.IsEmpty()) {
-    // Content Analysis doesn't expect to analyze an empty string.
-    // Just approve it.
-    return true;
-  }
-  RefPtr<mozilla::dom::WindowGlobalParent> window =
-      mozilla::dom::WindowGlobalParent::GetByInnerWindowId(aInnerWindowId);
-  if (!window) {
-    // The window has gone away in the meantime
-    return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-  }
-  nsCOMPtr<nsIContentAnalysisRequest> contentAnalysisRequest =
-      new ContentAnalysisRequest(
-          nsIContentAnalysisRequest::AnalysisType::eBulkDataEntry,
-          std::move(text), false, EmptyCString(), aDocumentURI,
-          nsIContentAnalysisRequest::OperationType::eClipboard, window);
-  nsresult rv = aContentAnalysis->AnalyzeContentRequestCallback(
-      contentAnalysisRequest, /* aAutoAcknowledge */ true, aResolver);
-  if (NS_FAILED(rv)) {
-    return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-  }
-  return true;
-}
-
-// Returning:
-//  - true means a content analysis request was fired
-//  - false means there is no file data in the transferable
-//  - NoContentAnalysisResult means there was an error
-static mozilla::Result<bool, mozilla::contentanalysis::NoContentAnalysisResult>
-CheckClipboardContentAnalysisAsFile(
-    uint64_t aInnerWindowId, SafeContentAnalysisResultCallback* aResolver,
-    nsIURI* aDocumentURI, nsIContentAnalysis* aContentAnalysis,
-    nsITransferable* aFileTrans) {
-  using namespace mozilla::contentanalysis;
-
-  nsCOMPtr<nsISupports> transferData;
-  nsresult rv =
-      aFileTrans->GetTransferData(kFileMime, getter_AddRefs(transferData));
-  nsString filePath;
-  if (NS_SUCCEEDED(rv)) {
-    if (nsCOMPtr<nsIFile> file = do_QueryInterface(transferData)) {
-      rv = file->GetPath(filePath);
-    } else {
-      MOZ_ASSERT_UNREACHABLE("clipboard data had kFileMime but no nsIFile!");
-      return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-    }
-  }
-  if (NS_FAILED(rv) || filePath.IsEmpty()) {
-    return false;
-  }
-  RefPtr<mozilla::dom::WindowGlobalParent> window =
-      mozilla::dom::WindowGlobalParent::GetByInnerWindowId(aInnerWindowId);
-  if (!window) {
-    // The window has gone away in the meantime
-    return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-  }
-  // Let the content analysis code calculate the digest
-  nsCOMPtr<nsIContentAnalysisRequest> contentAnalysisRequest =
-      new ContentAnalysisRequest(
-          nsIContentAnalysisRequest::AnalysisType::eBulkDataEntry,
-          std::move(filePath), true, EmptyCString(), aDocumentURI,
-          nsIContentAnalysisRequest::OperationType::eCustomDisplayString,
-          window);
-  rv = aContentAnalysis->AnalyzeContentRequestCallback(
-      contentAnalysisRequest,
-      /* aAutoAcknowledge */ true, aResolver);
-  if (NS_FAILED(rv)) {
-    return mozilla::Err(NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR);
-  }
-  return true;
-}
-
-static void CheckClipboardContentAnalysis(
-    mozilla::dom::WindowGlobalParent* aWindow, nsITransferable* aTransferable,
-    SafeContentAnalysisResultCallback* aResolver) {
-  using namespace mozilla::contentanalysis;
-
-  // Content analysis is only needed if an outside webpage has access to
-  // the data. So, skip content analysis if there is:
-  //  - no associated window (for example, scripted clipboard read by system
-  //  code)
-  //  - the window is a chrome docshell
-  //  - the window is being rendered in the parent process (for example,
-  //  about:support and the like)
-  if (!aWindow || aWindow->GetBrowsingContext()->IsChrome() ||
-      aWindow->IsInProcess()) {
-    aResolver->Callback(ContentAnalysisResult::FromNoResult(
-        NoContentAnalysisResult::
-            ALLOW_DUE_TO_CONTEXT_EXEMPT_FROM_CONTENT_ANALYSIS));
-    return;
-  }
-  nsCOMPtr<nsIContentAnalysis> contentAnalysis =
-      mozilla::components::nsIContentAnalysis::Service();
-  if (!contentAnalysis) {
-    aResolver->Callback(ContentAnalysisResult::FromNoResult(
-        NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR));
-    return;
-  }
-
-  bool contentAnalysisIsActive;
-  nsresult rv = contentAnalysis->GetIsActive(&contentAnalysisIsActive);
-  if (MOZ_LIKELY(NS_FAILED(rv) || !contentAnalysisIsActive)) {
-    aResolver->Callback(ContentAnalysisResult::FromNoResult(
-        NoContentAnalysisResult::ALLOW_DUE_TO_CONTENT_ANALYSIS_NOT_ACTIVE));
-    return;
-  }
-
-  nsCOMPtr<nsIURI> currentURI = aWindow->Canonical()->GetDocumentURI();
-  uint64_t innerWindowId = aWindow->InnerWindowId();
-  nsTArray<nsCString> flavors;
-  rv = aTransferable->FlavorsTransferableCanExport(flavors);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aResolver->Callback(ContentAnalysisResult::FromNoResult(
-        NoContentAnalysisResult::DENY_DUE_TO_OTHER_ERROR));
-    return;
-  }
-  bool keepChecking = true;
-  if (flavors.Contains(kFileMime)) {
-    auto fileResult = CheckClipboardContentAnalysisAsFile(
-        innerWindowId, aResolver, currentURI, contentAnalysis, aTransferable);
-
-    if (fileResult.isErr()) {
-      aResolver->Callback(
-          ContentAnalysisResult::FromNoResult(fileResult.unwrapErr()));
-      return;
-    }
-    keepChecking = !fileResult.unwrap();
-  }
-  if (keepChecking) {
-    // Failed to get the clipboard data as a file, so try as text
-    auto textResult = CheckClipboardContentAnalysisAsText(
-        innerWindowId, aResolver, currentURI, contentAnalysis, aTransferable);
-    if (textResult.isErr()) {
-      aResolver->Callback(
-          ContentAnalysisResult::FromNoResult(textResult.unwrapErr()));
-      return;
-    }
-    if (!textResult.unwrap()) {
-      // Couldn't get file or text data from this
-      aResolver->Callback(ContentAnalysisResult::FromNoResult(
-          NoContentAnalysisResult::ALLOW_DUE_TO_COULD_NOT_GET_DATA));
-      return;
-    }
-  }
-}
-
-static bool CheckClipboardContentAnalysisSync(
-    mozilla::dom::WindowGlobalParent* aWindow,
-    const nsCOMPtr<nsITransferable>& trans) {
-  bool requestDone = false;
-  RefPtr<nsIContentAnalysisResult> result;
-  auto callback = mozilla::MakeRefPtr<SafeContentAnalysisResultCallback>(
-      [&requestDone, &result](RefPtr<nsIContentAnalysisResult>&& aResult) {
-        result = std::move(aResult);
-        requestDone = true;
-      });
-  CheckClipboardContentAnalysis(aWindow, trans, callback);
-  mozilla::SpinEventLoopUntil("CheckClipboardContentAnalysisSync"_ns,
-                              [&requestDone]() -> bool { return requestDone; });
-  return result->GetShouldAllowContent();
-}
-
 nsBaseClipboard::nsBaseClipboard(const ClipboardCapabilities& aClipboardCaps)
     : mClipboardCaps(aClipboardCaps) {
   using mozilla::MakeUnique;
@@ -574,9 +349,9 @@ NS_IMPL_ISUPPORTS(nsBaseClipboard, nsIClipboard)
  * Sets the transferable object
  *
  */
-NS_IMETHODIMP nsBaseClipboard::SetData(nsITransferable* aTransferable,
-                                       nsIClipboardOwner* aOwner,
-                                       int32_t aWhichClipboard) {
+NS_IMETHODIMP nsBaseClipboard::SetData(
+    nsITransferable* aTransferable, nsIClipboardOwner* aOwner,
+    int32_t aWhichClipboard, mozilla::dom::WindowContext* aWindowContext) {
   NS_ASSERTION(aTransferable, "clipboard given a null transferable");
 
   MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
@@ -627,21 +402,22 @@ NS_IMETHODIMP nsBaseClipboard::SetData(nsITransferable* aTransferable,
     return result.unwrapErr();
   }
 
-  clipboardCache->Update(aTransferable, aOwner, result.unwrap());
+  clipboardCache->Update(aTransferable, aOwner, result.unwrap(),
+                         aWindowContext
+                             ? mozilla::Some(aWindowContext->InnerWindowId())
+                             : mozilla::Nothing());
   return NS_OK;
 }
 
 nsresult nsBaseClipboard::GetDataFromClipboardCache(
     nsITransferable* aTransferable, int32_t aClipboardType) {
   MOZ_ASSERT(aTransferable);
-  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
   MOZ_ASSERT(mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled());
 
   const auto* clipboardCache = GetClipboardCacheIfValid(aClipboardType);
   if (!clipboardCache) {
     return NS_ERROR_FAILURE;
   }
-
   return clipboardCache->GetData(aTransferable);
 }
 
@@ -671,8 +447,10 @@ NS_IMETHODIMP nsBaseClipboard::GetData(
     if (NS_SUCCEEDED(
             GetDataFromClipboardCache(aTransferable, aWhichClipboard))) {
       // maybe try to fill in more types? Is there a point?
-      if (!CheckClipboardContentAnalysisSync(aWindowContext->Canonical(),
-                                             aTransferable)) {
+      if (!mozilla::contentanalysis::ContentAnalysis::
+              CheckClipboardContentAnalysisSync(
+                  this, aWindowContext->Canonical(), aTransferable,
+                  aWhichClipboard)) {
         aTransferable->ClearAllData();
         return NS_ERROR_CONTENT_BLOCKED;
       }
@@ -686,8 +464,9 @@ NS_IMETHODIMP nsBaseClipboard::GetData(
   if (NS_FAILED(rv)) {
     return rv;
   }
-  if (!CheckClipboardContentAnalysisSync(aWindowContext->Canonical(),
-                                         aTransferable)) {
+  if (!mozilla::contentanalysis::ContentAnalysis::
+          CheckClipboardContentAnalysisSync(this, aWindowContext->Canonical(),
+                                            aTransferable, aWhichClipboard)) {
     aTransferable->ClearAllData();
     return NS_ERROR_CONTENT_BLOCKED;
   }
@@ -795,7 +574,7 @@ NS_IMETHODIMP nsBaseClipboard::AsyncGetData(
     nsCOMPtr<nsITransferable> trans = clipboardCache->GetTransferable();
     MOZ_ASSERT(trans);
 
-    if (nsCOMPtr<nsIPrincipal> principal = trans->GetRequestingPrincipal()) {
+    if (nsCOMPtr<nsIPrincipal> principal = trans->GetDataPrincipal()) {
       if (aRequestingPrincipal->Subsumes(principal)) {
         MOZ_CLIPBOARD_LOG("%s: native clipboard data is from same-origin page.",
                           __FUNCTION__);
@@ -1228,7 +1007,8 @@ NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetData(
   MOZ_ASSERT(mClipboard);
 
   auto contentAnalysisCallback =
-      mozilla::MakeRefPtr<SafeContentAnalysisResultCallback>(
+      mozilla::MakeRefPtr<mozilla::contentanalysis::ContentAnalysis::
+                              SafeContentAnalysisResultCallback>(
           [transferable = nsCOMPtr{aTransferable},
            callback = nsCOMPtr{aCallback}](
               RefPtr<nsIContentAnalysisResult>&& aResult) {
@@ -1249,10 +1029,11 @@ NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetData(
     MOZ_DIAGNOSTIC_ASSERT(clipboardCache->GetSequenceNumber() ==
                           mSequenceNumber);
     if (NS_SUCCEEDED(clipboardCache->GetData(aTransferable))) {
-      CheckClipboardContentAnalysis(mRequestingWindowContext
-                                        ? mRequestingWindowContext->Canonical()
-                                        : nullptr,
-                                    aTransferable, contentAnalysisCallback);
+      mozilla::contentanalysis::ContentAnalysis::CheckClipboardContentAnalysis(
+          mClipboard,
+          mRequestingWindowContext ? mRequestingWindowContext->Canonical()
+                                   : nullptr,
+          aTransferable, mClipboardType, contentAnalysisCallback);
       return NS_OK;
     }
 
@@ -1278,11 +1059,13 @@ NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetData(
           callback->OnComplete(NS_ERROR_FAILURE);
           return;
         }
-        CheckClipboardContentAnalysis(
-            self->mRequestingWindowContext
-                ? self->mRequestingWindowContext->Canonical()
-                : nullptr,
-            transferable, contentAnalysisCallback);
+        mozilla::contentanalysis::ContentAnalysis::
+            CheckClipboardContentAnalysis(
+                self->mClipboard,
+                self->mRequestingWindowContext
+                    ? self->mRequestingWindowContext->Canonical()
+                    : nullptr,
+                transferable, self->mClipboardType, contentAnalysisCallback);
       });
   return NS_OK;
 }
@@ -1320,6 +1103,13 @@ bool nsBaseClipboard::AsyncGetClipboardData::IsValid() {
   return true;
 }
 
+mozilla::Maybe<uint64_t> nsBaseClipboard::GetClipboardCacheInnerWindowId(
+    int32_t aClipboardType) {
+  auto* clipboardCache = GetClipboardCacheIfValid(aClipboardType);
+  return clipboardCache ? clipboardCache->GetInnerWindowId()
+                        : mozilla::Nothing();
+}
+
 nsBaseClipboard::ClipboardCache* nsBaseClipboard::GetClipboardCacheIfValid(
     int32_t aClipboardType) {
   MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
diff --git a/widget/nsBaseClipboard.h b/widget/nsBaseClipboard.h
index ffa68d6240..625421c342 100644
--- a/widget/nsBaseClipboard.h
+++ b/widget/nsBaseClipboard.h
@@ -14,11 +14,11 @@
 #include "nsITransferable.h"
 #include "nsCOMPtr.h"
 
-static mozilla::LazyLogModule sWidgetClipboardLog("WidgetClipboard");
+extern mozilla::LazyLogModule gWidgetClipboardLog;
 #define MOZ_CLIPBOARD_LOG(...) \
-  MOZ_LOG(sWidgetClipboardLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+  MOZ_LOG(gWidgetClipboardLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
 #define MOZ_CLIPBOARD_LOG_ENABLED() \
-  MOZ_LOG_TEST(sWidgetClipboardLog, mozilla::LogLevel::Debug)
+  MOZ_LOG_TEST(gWidgetClipboardLog, mozilla::LogLevel::Debug)
 
 class nsITransferable;
 class nsIClipboardOwner;
@@ -42,9 +42,12 @@ class nsBaseClipboard : public nsIClipboard {
   NS_DECL_ISUPPORTS
 
   // nsIClipboard
-  NS_IMETHOD SetData(nsITransferable* aTransferable, nsIClipboardOwner* aOwner,
-                     int32_t aWhichClipboard) override final;
+  NS_IMETHOD SetData(
+      nsITransferable* aTransferable, nsIClipboardOwner* aOwner,
+      int32_t aWhichClipboard,
+      mozilla::dom::WindowContext* aWindowContext) override final;
   NS_IMETHOD AsyncSetData(int32_t aWhichClipboard,
+                          mozilla::dom::WindowContext* aSettingWindowContext,
                           nsIAsyncClipboardRequestCallback* aCallback,
                           nsIAsyncSetClipboardData** _retval) override final;
   NS_IMETHOD GetData(
@@ -75,6 +78,9 @@ class nsBaseClipboard : public nsIClipboard {
   using HasMatchingFlavorsCallback = mozilla::MoveOnlyFunction<void(
       mozilla::Result<nsTArray<nsCString>, nsresult>)>;
 
+  mozilla::Maybe<uint64_t> GetClipboardCacheInnerWindowId(
+      int32_t aClipboardType);
+
  protected:
   virtual ~nsBaseClipboard();
 
@@ -106,6 +112,7 @@ class nsBaseClipboard : public nsIClipboard {
     NS_DECL_NSIASYNCSETCLIPBOARDDATA
 
     AsyncSetClipboardData(int32_t aClipboardType, nsBaseClipboard* aClipboard,
+                          mozilla::dom::WindowContext* aRequestingWindowContext,
                           nsIAsyncClipboardRequestCallback* aCallback);
 
    private:
@@ -123,6 +130,7 @@ class nsBaseClipboard : public nsIClipboard {
     // NotifyCallback()) once nsBaseClipboard stops tracking us. This is
     // also used to indicate whether this request is valid.
     nsBaseClipboard* mClipboard;
+    RefPtr<mozilla::dom::WindowContext> mWindowContext;
     // mCallback will be nullified once the callback is notified to ensure the
     // callback is only notified once.
     nsCOMPtr<nsIAsyncClipboardRequestCallback> mCallback;
@@ -172,22 +180,26 @@ class nsBaseClipboard : public nsIClipboard {
      */
     void Clear();
     void Update(nsITransferable* aTransferable,
-                nsIClipboardOwner* aClipboardOwner, int32_t aSequenceNumber) {
+                nsIClipboardOwner* aClipboardOwner, int32_t aSequenceNumber,
+                mozilla::Maybe<uint64_t> aInnerWindowId) {
       // Clear first to notify the old clipboard owner.
       Clear();
       mTransferable = aTransferable;
       mClipboardOwner = aClipboardOwner;
       mSequenceNumber = aSequenceNumber;
+      mInnerWindowId = aInnerWindowId;
     }
     nsITransferable* GetTransferable() const { return mTransferable; }
     nsIClipboardOwner* GetClipboardOwner() const { return mClipboardOwner; }
     int32_t GetSequenceNumber() const { return mSequenceNumber; }
+    mozilla::Maybe<uint64_t> GetInnerWindowId() const { return mInnerWindowId; }
     nsresult GetData(nsITransferable* aTransferable) const;
 
    private:
     nsCOMPtr<nsITransferable> mTransferable;
     nsCOMPtr<nsIClipboardOwner> mClipboardOwner;
     int32_t mSequenceNumber = -1;
+    mozilla::Maybe<uint64_t> mInnerWindowId;
   };
 
   void MaybeRetryGetAvailableFlavors(
@@ -203,7 +215,6 @@ class nsBaseClipboard : public nsIClipboard {
       int32_t aClipboardType);
   nsresult GetDataFromClipboardCache(nsITransferable* aTransferable,
                                      int32_t aClipboardType);
-
   void RequestUserConfirmation(int32_t aClipboardType,
                                const nsTArray<nsCString>& aFlavorList,
                                mozilla::dom::WindowContext* aWindowContext,
diff --git a/widget/nsBaseDragService.cpp b/widget/nsBaseDragService.cpp
index 22ed844595..c79d5bbb6d 100644
--- a/widget/nsBaseDragService.cpp
+++ b/widget/nsBaseDragService.cpp
@@ -368,7 +368,7 @@ nsBaseDragService::InvokeDragSession(
       nsCOMPtr<nsITransferable> trans =
           do_CreateInstance("@mozilla.org/widget/transferable;1");
       trans->Init(nullptr);
-      trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
+      trans->SetDataPrincipal(mSourceNode->NodePrincipal());
       trans->SetContentPolicyType(mContentPolicyType);
       trans->SetCookieJarSettings(aCookieJarSettings);
       mutableArray->AppendElement(trans);
@@ -378,8 +378,8 @@ nsBaseDragService::InvokeDragSession(
       nsCOMPtr<nsITransferable> trans =
           do_QueryElementAt(aTransferableArray, i);
       if (trans) {
-        // Set the requestingPrincipal on the transferable.
-        trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
+        // Set the dataPrincipal on the transferable.
+        trans->SetDataPrincipal(mSourceNode->NodePrincipal());
         trans->SetContentPolicyType(mContentPolicyType);
         trans->SetCookieJarSettings(aCookieJarSettings);
       }
diff --git a/widget/nsClipboardHelper.cpp b/widget/nsClipboardHelper.cpp
index 3439adef48..87e697a4c6 100644
--- a/widget/nsClipboardHelper.cpp
+++ b/widget/nsClipboardHelper.cpp
@@ -36,9 +36,10 @@ nsClipboardHelper::~nsClipboardHelper() {
  *****************************************************************************/
 
 NS_IMETHODIMP
-nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
-                                         int32_t aClipboardID,
-                                         SensitiveData aSensitive) {
+nsClipboardHelper::CopyStringToClipboard(
+    const nsAString& aString, int32_t aClipboardID,
+    mozilla::dom::WindowContext* aSettingWindowContext,
+    SensitiveData aSensitive) {
   nsresult rv;
 
   // get the clipboard
@@ -92,20 +93,22 @@ nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
   NS_ENSURE_SUCCESS(rv, rv);
 
   // put the transferable on the clipboard
-  rv = clipboard->SetData(trans, nullptr, aClipboardID);
+  rv = clipboard->SetData(trans, nullptr, aClipboardID, aSettingWindowContext);
   NS_ENSURE_SUCCESS(rv, rv);
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
-nsClipboardHelper::CopyString(const nsAString& aString,
-                              SensitiveData aSensitive) {
+nsClipboardHelper::CopyString(
+    const nsAString& aString,
+    mozilla::dom::WindowContext* aSettingWindowContext,
+    SensitiveData aSensitive) {
   nsresult rv;
 
   // copy to the global clipboard. it's bad if this fails in any way.
   rv = CopyStringToClipboard(aString, nsIClipboard::kGlobalClipboard,
-                             aSensitive);
+                             aSettingWindowContext, aSensitive);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // unix also needs us to copy to the selection clipboard. this will
@@ -117,7 +120,8 @@ nsClipboardHelper::CopyString(const nsAString& aString,
   // if this fails in any way other than "not being unix", we'll get
   // the assertion we need in CopyStringToClipboard, and we needn't
   // assert again here.
-  CopyStringToClipboard(aString, nsIClipboard::kSelectionClipboard, aSensitive);
+  CopyStringToClipboard(aString, nsIClipboard::kSelectionClipboard,
+                        aSettingWindowContext, aSensitive);
 
   return NS_OK;
 }
diff --git a/widget/nsClipboardProxy.cpp b/widget/nsClipboardProxy.cpp
index 3b27d5954d..5855374566 100644
--- a/widget/nsClipboardProxy.cpp
+++ b/widget/nsClipboardProxy.cpp
@@ -32,7 +32,8 @@ nsClipboardProxy::nsClipboardProxy() : mClipboardCaps(false, false, false) {}
 
 NS_IMETHODIMP
 nsClipboardProxy::SetData(nsITransferable* aTransferable,
-                          nsIClipboardOwner* anOwner, int32_t aWhichClipboard) {
+                          nsIClipboardOwner* anOwner, int32_t aWhichClipboard,
+                          mozilla::dom::WindowContext* aWindowContext) {
 #if defined(ACCESSIBILITY) && defined(XP_WIN)
   a11y::Compatibility::SuppressA11yForClipboardCopy();
 #endif
@@ -41,17 +42,19 @@ nsClipboardProxy::SetData(nsITransferable* aTransferable,
   IPCTransferable ipcTransferable;
   nsContentUtils::TransferableToIPCTransferable(aTransferable, &ipcTransferable,
                                                 false, nullptr);
-  child->SendSetClipboard(std::move(ipcTransferable), aWhichClipboard);
+  child->SendSetClipboard(std::move(ipcTransferable), aWhichClipboard,
+                          aWindowContext);
   return NS_OK;
 }
 
 NS_IMETHODIMP nsClipboardProxy::AsyncSetData(
-    int32_t aWhichClipboard, nsIAsyncClipboardRequestCallback* aCallback,
+    int32_t aWhichClipboard, mozilla::dom::WindowContext* aSettingWindowContext,
+    nsIAsyncClipboardRequestCallback* aCallback,
     nsIAsyncSetClipboardData** _retval) {
   RefPtr<ClipboardWriteRequestChild> request =
       MakeRefPtr<ClipboardWriteRequestChild>(aCallback);
   ContentChild::GetSingleton()->SendPClipboardWriteRequestConstructor(
-      request, aWhichClipboard);
+      request, aWhichClipboard, aSettingWindowContext);
   request.forget(_retval);
   return NS_OK;
 }
@@ -69,12 +72,18 @@ nsClipboardProxy::GetData(nsITransferable* aTransferable,
   nsTArray<nsCString> types;
   aTransferable->FlavorsTransferableCanImport(types);
 
-  IPCTransferableData transferable;
-  ContentChild::GetSingleton()->SendGetClipboard(types, aWhichClipboard,
-                                                 aWindowContext, &transferable);
+  IPCTransferableDataOrError transferableOrError;
+  ContentChild::GetSingleton()->SendGetClipboard(
+      types, aWhichClipboard, aWindowContext, &transferableOrError);
+
+  if (transferableOrError.type() == IPCTransferableDataOrError::Tnsresult) {
+    MOZ_ASSERT(NS_FAILED(transferableOrError.get_nsresult()));
+    return transferableOrError.get_nsresult();
+  }
+
   return nsContentUtils::IPCTransferableDataToTransferable(
-      transferable, false /* aAddDataFlavor */, aTransferable,
-      false /* aFilterUnknownFlavors */);
+      transferableOrError.get_IPCTransferableData(), false /* aAddDataFlavor */,
+      aTransferable, false /* aFilterUnknownFlavors */);
 }
 
 namespace {
diff --git a/widget/nsIBaseWindow.idl b/widget/nsIBaseWindow.idl
index 3cf7193788..3e0dadbdd5 100644
--- a/widget/nsIBaseWindow.idl
+++ b/widget/nsIBaseWindow.idl
@@ -161,7 +161,7 @@ interface nsIBaseWindow : nsISupports
    *
    * @see DimensionRequest
    */
-  void setDimensions(in DimensionRequest aRequest);
+  [noscript] void setDimensions(in DimensionRequest aRequest);
 
   /**
    * Gets the dimensions of the window. The caller may pass nullptr for any
@@ -178,7 +178,7 @@ interface nsIBaseWindow : nsISupports
    *
    * @see DimensionRequest
    */
-  void getDimensions(in DimensionKind aDimensionKind, out long aX, out long aY, out long aCX, out long aCY);
+  [noscript] void getDimensions(in DimensionKind aDimensionKind, out long aX, out long aY, out long aCX, out long aCY);
 
   /**
    * Tell the window to repaint itself
@@ -210,7 +210,7 @@ interface nsIBaseWindow : nsISupports
   On controls that don't support setting nativeWindow parents, setting this
   will return a NS_ERROR_NOT_IMPLEMENTED error.
   */
-  attribute nativeWindow parentNativeWindow;
+  [noscript] attribute nativeWindow parentNativeWindow;
 
   /*
   This is the handle (HWND, GdkWindow*, ...) to the native window of the
diff --git a/widget/nsIClipboard.idl b/widget/nsIClipboard.idl
index a34f0f9298..fc1f8bf8c3 100644
--- a/widget/nsIClipboard.idl
+++ b/widget/nsIClipboard.idl
@@ -115,20 +115,28 @@ interface nsIClipboard : nsISupports
     * @param  aTransferable The transferable
     * @param  anOwner The owner of the transferable
     * @param  aWhichClipboard Specifies the clipboard to which this operation applies.
-    * @result NS_Ok if no errors
+    * @param  aSettingWindowContext [optional]
+    *         The window context that is setting the clipboard, if any. This is used
+    *         to possibly bypass Content Analysis if a set clipboard and get clipboard
+    *         operation are done on the same page.
+    * @result NS_OK if no errors
     */
 
-    void setData ( in nsITransferable aTransferable, in nsIClipboardOwner anOwner,
-                    in long aWhichClipboard ) ;
+    void setData (in nsITransferable aTransferable, in nsIClipboardOwner anOwner,
+                  in long aWhichClipboard, [optional] in WindowContext aSettingWindowContext);
 
     /**
-     * Requests setting data to the native clipboard. The acutal set occur
+     * Requests setting data to the native clipboard. The actual set occurs
      * when the data is provided by calling nsIAsyncSetClipboardData::setData().
      * The result will be notified by nsIClipboardCallback. A new set request
      * will cancel any prior pending requests, if any exist.
      *
      * @param  aWhichClipboard
      *         Specifies the clipboard to which this operation applies.
+     * @param  aSettingWindowContext [optional]
+     *         The window context that is setting the clipboard, if any. This is used
+     *         to possibly bypass Content Analysis if a set clipboard and get clipboard
+     *         operation are done on the same page.
      * @param  aCallback [optional]
      *         The callback object that will be notified upon completion.
      * @return nsIAsyncSetClipboardData
@@ -136,6 +144,7 @@ interface nsIClipboard : nsISupports
      *         data is provided by calling nsIAsyncSetClipboardData::setData().
      */
     nsIAsyncSetClipboardData asyncSetData(in long aWhichClipboard,
+                                          [optional] in WindowContext aSettingWindowContext,
                                           [optional] in nsIAsyncClipboardRequestCallback aCallback);
 
    /**
diff --git a/widget/nsIClipboardHelper.idl b/widget/nsIClipboardHelper.idl
index ed4af112f1..370c652b31 100644
--- a/widget/nsIClipboardHelper.idl
+++ b/widget/nsIClipboardHelper.idl
@@ -29,17 +29,29 @@ interface nsIClipboardHelper : nsISupports
    * @param aString, the string to copy to the clipboard
    * @param aClipboardID, the ID of the clipboard to copy to
    *        (eg. kSelectionClipboard -- see nsIClipboard.idl)
+   * @param aSettingWindowContext
+   *         The window context that is setting the clipboard, if any. This is used
+   *         to possibly bypass Content Analysis if a set clipboard and get clipboard
+   *         operation are done on the same page.
    * @param aSensitive, optional flag to indicate that data is sensitive, like a password.
    *        That will exclude data from Cloud Clipboard/Clipboard History on Windows.
    */
   void copyStringToClipboard(in AString aString, in long aClipboardID,
+                             [optional] in WindowContext aSettingWindowContext,
                              [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
 
   /**
    * copy string to (default) clipboard
    *
    * @param aString, the string to copy to the clipboard
+   * @param aSettingWindowContext
+   *         The window context that is setting the clipboard, if any. This is used
+   *         to possibly bypass Content Analysis if a set clipboard and get clipboard
+   *         operation are done on the same page.
+   * @param aSensitive, optional flag to indicate that data is sensitive, like a password.
+   *        That will exclude data from Cloud Clipboard/Clipboard History on Windows.
    */
   void copyString(in AString aString,
+                  [optional] in WindowContext aSettingWindowContext,
                   [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
 };
diff --git a/widget/nsIDeviceContextSpec.cpp b/widget/nsIDeviceContextSpec.cpp
index 5ab442415d..2ec5946bb0 100644
--- a/widget/nsIDeviceContextSpec.cpp
+++ b/widget/nsIDeviceContextSpec.cpp
@@ -58,8 +58,8 @@ gfxPoint nsIDeviceContextSpec::GetPrintingTranslate() {
 }
 
 RefPtr<PrintEndDocumentPromise>
-nsIDeviceContextSpec::EndDocumentPromiseFromResult(nsresult aResult,
-                                                   const char* aSite) {
+nsIDeviceContextSpec::EndDocumentPromiseFromResult(
+    nsresult aResult, mozilla::StaticString aSite) {
   return NS_SUCCEEDED(aResult)
              ? PrintEndDocumentPromise::CreateAndResolve(true, aSite)
              : PrintEndDocumentPromise::CreateAndReject(aResult, aSite);
diff --git a/widget/nsIDeviceContextSpec.h b/widget/nsIDeviceContextSpec.h
index 6afe4ea850..33ebaecd62 100644
--- a/widget/nsIDeviceContextSpec.h
+++ b/widget/nsIDeviceContextSpec.h
@@ -95,7 +95,7 @@ class nsIDeviceContextSpec : public nsISupports {
       const char* aCallSite, AsyncEndDocumentFunction aFunction);
 
   static RefPtr<mozilla::gfx::PrintEndDocumentPromise>
-  EndDocumentPromiseFromResult(nsresult aResult, const char* aSite);
+  EndDocumentPromiseFromResult(nsresult aResult, mozilla::StaticString aSite);
 
   nsCOMPtr<nsIPrintSettings> mPrintSettings;
 
diff --git a/widget/nsIDragService.idl b/widget/nsIDragService.idl
index a35d3128a8..619c8f8a82 100644
--- a/widget/nsIDragService.idl
+++ b/widget/nsIDragService.idl
@@ -126,7 +126,7 @@ interface nsIDragService : nsISupports
    *
    * Note: This method is deprecated for non-native code.
    */
-  [can_run_script]
+  [noscript, can_run_script]
   void invokeDragSessionWithSelection(in Selection aSelection,
                                       in nsIPrincipal aPrincipal,
                                       in nsIContentSecurityPolicy aCsp,
diff --git a/widget/nsIJumpListBuilder.idl b/widget/nsIJumpListBuilder.idl
index 1b7b93e5e7..a52f09d7da 100644
--- a/widget/nsIJumpListBuilder.idl
+++ b/widget/nsIJumpListBuilder.idl
@@ -100,9 +100,9 @@ interface nsIJumpListBuilder : nsISupports
    */
   [implicit_jscontext]
   Promise populateJumpList(
-    in Array<jsval> aTaskDescriptions,
+    in jsval aTaskDescriptions,
     in AString aCustomTitle,
-    in Array<jsval> aCustomDescriptions
+    in jsval aCustomDescriptions
   );
 
   /**
diff --git a/widget/nsIScreen.idl b/widget/nsIScreen.idl
index af8371edb3..619b8bc284 100644
--- a/widget/nsIScreen.idl
+++ b/widget/nsIScreen.idl
@@ -75,7 +75,7 @@ interface nsIScreen : nsISupports
   /**
    * ScreenColorGamut is native type, which cannot be declared [infallible].
    */
-  readonly attribute ScreenColorGamut colorGamut;
+  [noscript] readonly attribute ScreenColorGamut colorGamut;
 
   /**
    * The number of device pixels per desktop pixel for this screen (for
diff --git a/widget/nsITransferable.idl b/widget/nsITransferable.idl
index 0a8419c4bb..c6e424d7cb 100644
--- a/widget/nsITransferable.idl
+++ b/widget/nsITransferable.idl
@@ -203,9 +203,8 @@ interface nsITransferable : nsISupports
    * node principal of the source DOM node from which this transferable was
    * created, or the principal of the global from which this transferable was
    * created.
-   * XXXedgar: Rename it to something more generic, bug 1867636.
    */
-  [notxpcom, nostdcall] attribute nsIPrincipal requestingPrincipal;
+  [notxpcom, nostdcall] attribute nsIPrincipal dataPrincipal;
 
   /**
    * the contentPolicyType for this transferable.
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
index 06eab558eb..29c127c146 100644
--- a/widget/nsIWidget.h
+++ b/widget/nsIWidget.h
@@ -1397,6 +1397,8 @@ class nsIWidget : public nsISupports {
                               const nsAString& xulWinClass,
                               const nsAString& xulWinName) = 0;
 
+  virtual void SetIsEarlyBlankWindow(bool) {}
+
   /**
    * Enables/Disables system capture of any and all events that would cause a
    * popup to be rolled up. aListener should be set to a non-null value for
diff --git a/widget/nsIWidgetListener.cpp b/widget/nsIWidgetListener.cpp
index b9f236f159..13eba4eeeb 100644
--- a/widget/nsIWidgetListener.cpp
+++ b/widget/nsIWidgetListener.cpp
@@ -36,8 +36,6 @@ void nsIWidgetListener::SizeModeChanged(nsSizeMode aSizeMode) {}
 void nsIWidgetListener::SafeAreaInsetsChanged(const mozilla::ScreenIntMargin&) {
 }
 
-void nsIWidgetListener::UIResolutionChanged() {}
-
 #if defined(MOZ_WIDGET_ANDROID)
 void nsIWidgetListener::DynamicToolbarMaxHeightChanged(ScreenIntCoord aHeight) {
 }
diff --git a/widget/nsIWidgetListener.h b/widget/nsIWidgetListener.h
index aff753aaec..950d4b4622 100644
--- a/widget/nsIWidgetListener.h
+++ b/widget/nsIWidgetListener.h
@@ -81,12 +81,6 @@ class nsIWidgetListener {
    */
   virtual void SizeModeChanged(nsSizeMode aSizeMode);
 
-  /**
-   * Called when the DPI (device resolution scaling factor) is changed,
-   * such that UI elements may need to be rescaled.
-   */
-  virtual void UIResolutionChanged();
-
 #if defined(MOZ_WIDGET_ANDROID)
   virtual void DynamicToolbarMaxHeightChanged(mozilla::ScreenIntCoord aHeight);
   virtual void DynamicToolbarOffsetChanged(mozilla::ScreenIntCoord aOffset);
diff --git a/widget/nsNativeTheme.cpp b/widget/nsNativeTheme.cpp
index 6900414ff3..fcb30f5a7b 100644
--- a/widget/nsNativeTheme.cpp
+++ b/widget/nsNativeTheme.cpp
@@ -120,6 +120,7 @@ NS_IMPL_ISUPPORTS(nsNativeTheme, nsITimerCallback, nsINamed)
     case StyleAppearance::Menulist:
     case StyleAppearance::NumberInput:
     case StyleAppearance::Textfield:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Searchfield:
     case StyleAppearance::Textarea: {
       if (CheckBooleanAttr(aFrame, nsGkAtoms::focused)) {
diff --git a/widget/nsTransferable.cpp b/widget/nsTransferable.cpp
index 58a8630801..b1e1f60ade 100644
--- a/widget/nsTransferable.cpp
+++ b/widget/nsTransferable.cpp
@@ -511,17 +511,16 @@ void nsTransferable::SetIsPrivateData(bool aIsPrivateData) {
   mPrivateData = aIsPrivateData;
 }
 
-nsIPrincipal* nsTransferable::GetRequestingPrincipal() {
+nsIPrincipal* nsTransferable::GetDataPrincipal() {
   MOZ_ASSERT(mInitialized);
 
-  return mRequestingPrincipal;
+  return mDataPrincipal;
 }
 
-void nsTransferable::SetRequestingPrincipal(
-    nsIPrincipal* aRequestingPrincipal) {
+void nsTransferable::SetDataPrincipal(nsIPrincipal* aDataPrincipal) {
   MOZ_ASSERT(mInitialized);
 
-  mRequestingPrincipal = aRequestingPrincipal;
+  mDataPrincipal = aDataPrincipal;
 }
 
 nsContentPolicyType nsTransferable::GetContentPolicyType() {
diff --git a/widget/nsTransferable.h b/widget/nsTransferable.h
index 02f2b0459c..191be3e74a 100644
--- a/widget/nsTransferable.h
+++ b/widget/nsTransferable.h
@@ -80,7 +80,7 @@ class nsTransferable : public nsITransferable {
   nsTArray<DataStruct> mDataArray;
   nsCOMPtr<nsIFormatConverter> mFormatConv;
   bool mPrivateData;
-  nsCOMPtr<nsIPrincipal> mRequestingPrincipal;
+  nsCOMPtr<nsIPrincipal> mDataPrincipal;
   nsContentPolicyType mContentPolicyType;
   nsCOMPtr<nsICookieJarSettings> mCookieJarSettings;
   nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
diff --git a/widget/nsXPLookAndFeel.cpp b/widget/nsXPLookAndFeel.cpp
index 0c5b5207f2..cb34f7b067 100644
--- a/widget/nsXPLookAndFeel.cpp
+++ b/widget/nsXPLookAndFeel.cpp
@@ -146,7 +146,6 @@ static const char sIntPrefs[][45] = {
     "ui.treeLazyScrollDelay",
     "ui.treeScrollDelay",
     "ui.treeScrollLinesMax",
-    "accessibility.tabfocus",  // Weird one...
     "ui.chosenMenuItemsShouldBlink",
     "ui.windowsAccentColorInTitlebar",
     "ui.macBigSurTheme",
@@ -527,9 +526,6 @@ void nsXPLookAndFeel::Init() {
   //     for each types.  Then, we could reduce the unnecessary loop from
   //     nsXPLookAndFeel::OnPrefChanged().
   Preferences::RegisterPrefixCallback(OnPrefChanged, "ui.");
-  // We really do just want the accessibility.tabfocus pref, not other prefs
-  // that start with that string.
-  Preferences::RegisterCallback(OnPrefChanged, "accessibility.tabfocus");
 
   for (const auto& pref : kMediaQueryPrefs) {
     Preferences::RegisterCallback(
@@ -1237,8 +1233,7 @@ void LookAndFeel::DoHandleGlobalThemeChange() {
   //
   // We can use the *DoNotUseDirectly functions directly here, because we want
   // to notify all possible themes in a given process (but just once).
-  if (XRE_IsParentProcess() ||
-      !StaticPrefs::widget_non_native_theme_enabled()) {
+  if (XRE_IsParentProcess()) {
     if (nsCOMPtr<nsITheme> theme = do_GetNativeThemeDoNotUseDirectly()) {
       theme->ThemeChanged();
     }
diff --git a/widget/reftests/reftest.list b/widget/reftests/reftest.list
index dc788a31aa..2170fec443 100644
--- a/widget/reftests/reftest.list
+++ b/widget/reftests/reftest.list
@@ -6,4 +6,4 @@ load 664925.xhtml
 pref(apz.allow_zooming,true) pref(ui.useOverlayScrollbars,0) skip-if(!cocoaWidget) != scaled-scrollbar.html about:blank
 
 # Test that scrollbar buttons are inhibited on Linux using the non-native theme.
-skip-if(!gtkWidget) pref(widget.non-native-theme.enabled,true) test-pref(ui.scrollArrowStyle,4097) ref-pref(ui.scrollArrowStyle,0) == scrollbar-buttons.html scrollbar-buttons.html
+skip-if(!gtkWidget) test-pref(ui.scrollArrowStyle,4097) ref-pref(ui.scrollArrowStyle,0) == scrollbar-buttons.html scrollbar-buttons.html
diff --git a/widget/tests/browser/browser_test_InputContextURI.js b/widget/tests/browser/browser_test_InputContextURI.js
index 52f05d90f9..ccdfc86def 100644
--- a/widget/tests/browser/browser_test_InputContextURI.js
+++ b/widget/tests/browser/browser_test_InputContextURI.js
@@ -86,6 +86,9 @@ add_task(async () => {
   await test_url_bar_url("check after remote content sets the URI");
 });
 add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.security.https_first", false]],
+  });
   await test_input_in_http_or_https(false);
 });
 
diff --git a/widget/tests/browser/browser_test_scrollbar_colors.js b/widget/tests/browser/browser_test_scrollbar_colors.js
index 2152412071..458cadd84e 100644
--- a/widget/tests/browser/browser_test_scrollbar_colors.js
+++ b/widget/tests/browser/browser_test_scrollbar_colors.js
@@ -27,15 +27,6 @@ add_task(async () => {
 
     // == Native theme ==
 
-    const WIN_REFERENCES = [
-      // Yellow background
-      ["255,255,0", 6889],
-      // Blue scrollbar face
-      ["0,0,255", 540],
-      // Cyan scrollbar track
-      ["0,255,255", 2487],
-    ];
-
     const MAC_REFERENCES = [
       // Yellow background
       ["255,255,0", 7225],
@@ -45,19 +36,9 @@ add_task(async () => {
       ["0,255,255", 1760],
     ];
 
-    // Values have been updated from 8100, 720, 1180 for linux1804
-    const LINUX_REFERENCES = [
-      // Yellow background
-      ["255,255,0", 7744],
-      // Blue scrollbar face
-      ["0,0,255", 1104],
-      // Cyan scrollbar track
-      ["0,255,255", 1152],
-    ];
-
     // == Non-native theme ==
 
-    const WIN10_NNT_REFERENCES = [
+    const WIN10_REFERENCES = [
       // Yellow background
       ["255,255,0", 6889],
       // Blue scrollbar face
@@ -66,7 +47,7 @@ add_task(async () => {
       ["0,255,255", 2355],
     ];
 
-    const WIN11_NNT_REFERENCES = [
+    const WIN11_REFERENCES = [
       // Yellow background
       ["255,255,0", 6889],
       // Blue scrollbar face
@@ -75,9 +56,7 @@ add_task(async () => {
       ["0,255,255", 2787],
     ];
 
-    const MAC_NNT_REFERENCES = MAC_REFERENCES;
-
-    const LINUX_NNT_REFERENCES = [
+    const LINUX_REFERENCES = [
       // Yellow background
       ["255,255,0", 7744],
       // Blue scrollbar face
@@ -116,23 +95,19 @@ add_task(async () => {
 
     let canvas = snapshotRect(content.window, outerRect);
     let stats = countPixels(canvas);
-    let isNNT = SpecialPowers.getBoolPref("widget.non-native-theme.enabled");
-
     let references;
     if (content.navigator.platform.startsWith("Win")) {
-      if (!isNNT) {
-        references = WIN_REFERENCES;
-      } else if (WindowsVersionInfo.get().buildNumber >= 22000) {
-        // Windows 11 NNT
-        references = WIN11_NNT_REFERENCES;
+      if (WindowsVersionInfo.get().buildNumber >= 22000) {
+        // Windows 11
+        references = WIN11_REFERENCES;
       } else {
-        // Windows 10 NNT
-        references = WIN10_NNT_REFERENCES;
+        // Windows 10
+        references = WIN10_REFERENCES;
       }
     } else if (content.navigator.platform.startsWith("Mac")) {
-      references = isNNT ? MAC_NNT_REFERENCES : MAC_REFERENCES;
+      references = MAC_REFERENCES;
     } else if (content.navigator.platform.startsWith("Linux")) {
-      references = isNNT ? LINUX_NNT_REFERENCES : LINUX_REFERENCES;
+      references = LINUX_REFERENCES;
     } else {
       ok(false, "Unsupported platform");
     }
diff --git a/widget/tests/file_test_clipboard.js b/widget/tests/file_test_clipboard.js
index 76bdbaa84d..4e720b6383 100644
--- a/widget/tests/file_test_clipboard.js
+++ b/widget/tests/file_test_clipboard.js
@@ -149,5 +149,20 @@ clipboardTypes.forEach(function (clipboardType) {
       // Clear all clipboard data.
       cleanupAllClipboard();
     });
+
+    add_task(function test_unsupport_flavor() {
+      try {
+        is(
+          getClipboardData("foo/bar", clipboardType),
+          null,
+          `Test getData for clipboard type ${clipboardType}`
+        );
+      } catch (e) {
+        ok(
+          false,
+          `getData should not throw error for clipboard type ${clipboardType}`
+        );
+      }
+    });
   }
 });
diff --git a/widget/tests/file_test_clipboard_asyncSetData.js b/widget/tests/file_test_clipboard_asyncSetData.js
index cceecd2c44..5eb73f90fa 100644
--- a/widget/tests/file_test_clipboard_asyncSetData.js
+++ b/widget/tests/file_test_clipboard_asyncSetData.js
@@ -21,7 +21,7 @@ clipboardTypes.forEach(function (type) {
             let priorResult;
             let priorRequest;
             let priorPromise = new Promise(resolve => {
-              priorRequest = clipboard.asyncSetData(type, {
+              priorRequest = clipboard.asyncSetData(type, null, {
                 QueryInterface: SpecialPowers.ChromeUtils.generateQI([
                   "nsIAsyncSetClipboardDataCallback",
                 ]),
@@ -119,7 +119,7 @@ clipboardTypes.forEach(function (type) {
 
       // Create a pending asyncSetData request
       let result;
-      let request = clipboard.asyncSetData(type, rv => {
+      let request = clipboard.asyncSetData(type, null, rv => {
         result = rv;
       });
 
diff --git a/widget/uikit/nsLookAndFeel.mm b/widget/uikit/nsLookAndFeel.mm
index 51a9a95b52..f720a8681e 100644
--- a/widget/uikit/nsLookAndFeel.mm
+++ b/widget/uikit/nsLookAndFeel.mm
@@ -282,9 +282,6 @@ nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
     case IntID::TreeScrollLinesMax:
       aResult = 3;
       break;
-    case IntID::TabFocusModel:
-      aResult = 1;  // default to just textboxes
-      break;
     case IntID::ScrollToClick:
       aResult = 0;
       break;
diff --git a/widget/windows/CompositorWidgetParent.cpp b/widget/windows/CompositorWidgetParent.cpp
index b25d30d9d5..d38125f4ca 100644
--- a/widget/windows/CompositorWidgetParent.cpp
+++ b/widget/windows/CompositorWidgetParent.cpp
@@ -149,16 +149,12 @@ mozilla::ipc::IPCResult CompositorWidgetParent::RecvNotifyVisibilityUpdated(
   return IPC_OK();
 }
 
-nsSizeMode CompositorWidgetParent::CompositorWidgetParent::GetWindowSizeMode()
-    const {
-  nsSizeMode sizeMode = mSizeMode;
-  return sizeMode;
+nsSizeMode CompositorWidgetParent::GetWindowSizeMode() const {
+  return mSizeMode;
 }
 
-bool CompositorWidgetParent::CompositorWidgetParent::GetWindowIsFullyOccluded()
-    const {
-  bool isFullyOccluded = mIsFullyOccluded;
-  return isFullyOccluded;
+bool CompositorWidgetParent::GetWindowIsFullyOccluded() const {
+  return mIsFullyOccluded;
 }
 
 mozilla::ipc::IPCResult CompositorWidgetParent::RecvClearTransparentWindow() {
diff --git a/widget/windows/GfxInfo.cpp b/widget/windows/GfxInfo.cpp
index 6d8429f1cc..bb9b19e3a1 100644
--- a/widget/windows/GfxInfo.cpp
+++ b/widget/windows/GfxInfo.cpp
@@ -1808,6 +1808,12 @@ const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
         V(10, 18, 15, 4256), V(10, 18, 15, 4293), "FEATURE_FAILURE_BUG_1833809",
         "Intel driver 10.18.15.*");
 
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelGen12,
+        nsIGfxInfo::FEATURE_REUSE_DECODER_DEVICE,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_BUG_1896823");
+
     ////////////////////////////////////
     // FEATURE_OVERLAY_VP_AUTO_HDR
 
diff --git a/widget/windows/JumpListBuilder.cpp b/widget/windows/JumpListBuilder.cpp
index e25c8c038f..69a46d5aad 100644
--- a/widget/windows/JumpListBuilder.cpp
+++ b/widget/windows/JumpListBuilder.cpp
@@ -18,6 +18,17 @@
 #include "nsServiceManagerUtils.h"
 #include "WinUtils.h"
 
+#ifdef __MINGW32__
+// The PKEY_Link_Arguments property key does not exist in the MINGW32
+// build configuration, so we define it ourselves here.
+#  define INITGUID  // This alters the behavior of DEFINE_PROPERTYKEY so that
+                    // we define PKEY_Link_Arguments rather than declare it.
+#  include <propkeydef.h>  // For DEFINE_PROPERTYKEY() definition
+DEFINE_PROPERTYKEY(PKEY_Link_Arguments, 0x436F2667, 0x14E2, 0x4FEB, 0xB3, 0x0A,
+                   0x14, 0x6C, 0x53, 0xB5, 0xB6, 0x74, 100);
+#  undef INITGUID
+#endif
+
 using mozilla::dom::Promise;
 using mozilla::dom::WindowsJumpListShortcutDescription;
 
@@ -291,15 +302,35 @@ JumpListBuilder::CheckForRemovals(JSContext* aCx, Promise** aPromise) {
 }
 
 NS_IMETHODIMP
-JumpListBuilder::PopulateJumpList(
-    const nsTArray<JS::Value>& aTaskDescriptions, const nsAString& aCustomTitle,
-    const nsTArray<JS::Value>& aCustomDescriptions, JSContext* aCx,
-    Promise** aPromise) {
+JumpListBuilder::PopulateJumpList(JS::Handle<JS::Value> aTaskDescriptions,
+                                  const nsAString& aCustomTitle,
+                                  JS::Handle<JS::Value> aCustomDescriptions,
+                                  JSContext* aCx, Promise** aPromise) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aPromise);
   MOZ_ASSERT(mIOThread);
 
-  if (aCustomDescriptions.Length() && aCustomTitle.IsEmpty()) {
+  if (!aTaskDescriptions.isObject() || !aCustomDescriptions.isObject()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  JS::Rooted<JSObject*> taskDescriptionsObj(aCx, &aTaskDescriptions.toObject());
+  JS::Rooted<JSObject*> customDescriptionsObj(aCx,
+                                              &aCustomDescriptions.toObject());
+
+  uint32_t taskDescriptionsLength = 0;
+  uint32_t customDescriptionsLength = 0;
+  if (NS_WARN_IF(!JS::GetArrayLength(aCx, taskDescriptionsObj,
+                                     &taskDescriptionsLength))) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (NS_WARN_IF(!JS::GetArrayLength(aCx, customDescriptionsObj,
+                                     &customDescriptionsLength))) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (customDescriptionsLength && aCustomTitle.IsEmpty()) {
     return NS_ERROR_INVALID_ARG;
   }
 
@@ -309,9 +340,11 @@ JumpListBuilder::PopulateJumpList(
   mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
 
   nsTArray<WindowsJumpListShortcutDescription> taskDescs;
-  for (auto& jsval : aTaskDescriptions) {
+  for (uint32_t arrayIndex = 0; arrayIndex < taskDescriptionsLength;
+       arrayIndex++) {
     JS::Rooted<JS::Value> rootedVal(aCx);
-    if (NS_WARN_IF(!dom::ToJSValue(aCx, jsval, &rootedVal))) {
+    if (NS_WARN_IF(
+            !JS_GetElement(aCx, taskDescriptionsObj, arrayIndex, &rootedVal))) {
       return NS_ERROR_INVALID_ARG;
     }
 
@@ -324,9 +357,11 @@ JumpListBuilder::PopulateJumpList(
   }
 
   nsTArray<WindowsJumpListShortcutDescription> customDescs;
-  for (auto& jsval : aCustomDescriptions) {
+  for (uint32_t arrayIndex = 0; arrayIndex < customDescriptionsLength;
+       arrayIndex++) {
     JS::Rooted<JS::Value> rootedVal(aCx);
-    if (NS_WARN_IF(!dom::ToJSValue(aCx, jsval, &rootedVal))) {
+    if (NS_WARN_IF(!JS_GetElement(aCx, customDescriptionsObj, arrayIndex,
+                                  &rootedVal))) {
       return NS_ERROR_INVALID_ARG;
     }
 
@@ -592,7 +627,14 @@ void JumpListBuilder::DoPopulateJumpList(
         reinterpret_cast<const wchar_t*>(aCustomTitle.BeginReading()),
         pCustomArray);
 
-    if (FAILED(hr)) {
+    // E_ACCESSDENIED might be returned if Windows is configured not to show
+    // recently opened items in the start menu or jump lists. In that case, we
+    // still want to populate the tasks, so we ignore the error and commit
+    // the list.
+    //
+    // See
+    // https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-icustomdestinationlist-appendcategory
+    if (FAILED(hr) && hr != E_ACCESSDENIED) {
       rv = NS_ERROR_UNEXPECTED;
       return;
     }
@@ -659,26 +701,47 @@ void JumpListBuilder::RemoveIconCacheAndGetJumplistShortcutURIs(
 
     if (FAILED(aObjArray->GetAt(idx, IID_IShellLinkW,
                                 static_cast<void**>(getter_AddRefs(pLink))))) {
+      NS_WARNING("Could not get a IShellLink from the IObjectArray");
       continue;
     }
 
-    wchar_t buf[MAX_PATH];
-    HRESULT hres = pLink->GetArguments(buf, MAX_PATH);
-    if (SUCCEEDED(hres)) {
-      LPWSTR* arglist;
-      int32_t numArgs;
-
-      arglist = ::CommandLineToArgvW(buf, &numArgs);
-      if (arglist && numArgs > 0) {
-        nsString spec(arglist[0]);
-        aURISpecs.AppendElement(std::move(spec));
-        ::LocalFree(arglist);
-      }
+    RefPtr<IPropertyStore> pPropStore = nullptr;
+    if (NS_WARN_IF(FAILED(pLink->QueryInterface(
+            IID_IPropertyStore,
+            static_cast<void**>(getter_AddRefs(pPropStore)))))) {
+      NS_WARNING("Could not get IPropertyStore from IShellLink");
+      continue;
+    }
+
+    PROPVARIANT pv;
+    PropVariantInit(&pv);
+    auto cleanupPropVariant = MakeScopeExit([&] { PropVariantClear(&pv); });
+    if (NS_WARN_IF(FAILED(pPropStore->GetValue(PKEY_Link_Arguments, &pv)))) {
+      NS_WARNING("Could not get PKEY_Link_Arguments from IPropertyStore");
+      continue;
+    }
+
+    if (pv.vt != VT_LPWSTR) {
+      NS_WARNING("Unexpected type returned for PKEY_Link_Arguments");
+      continue;
+    }
+
+    LPCWSTR args(char16ptr_t(pv.pwszVal));
+    LPWSTR* arglist;
+    int32_t numArgs;
+
+    arglist = ::CommandLineToArgvW(args, &numArgs);
+    if (arglist && numArgs > 0) {
+      nsString spec(arglist[0]);
+      aURISpecs.AppendElement(std::move(spec));
+      ::LocalFree(arglist);
     }
 
     int iconIdx = 0;
-    hres = pLink->GetIconLocation(buf, MAX_PATH, &iconIdx);
+    wchar_t buf[MAX_PATH + 1];
+    HRESULT hres = pLink->GetIconLocation(buf, MAX_PATH, &iconIdx);
     if (SUCCEEDED(hres)) {
+      buf[MAX_PATH] = '\0';
       nsDependentString spec(buf);
       DeleteIconFromDisk(spec);
     }
diff --git a/widget/windows/RemoteBackbuffer.cpp b/widget/windows/RemoteBackbuffer.cpp
index 56a8bae0fe..2d53570c3e 100644
--- a/widget/windows/RemoteBackbuffer.cpp
+++ b/widget/windows/RemoteBackbuffer.cpp
@@ -89,6 +89,8 @@ class SharedImage {
   }
 
   bool Initialize(int32_t aWidth, int32_t aHeight) {
+    MOZ_ASSERT(aWidth);
+    MOZ_ASSERT(aHeight);
     MOZ_ASSERT(aWidth > 0);
     MOZ_ASSERT(aHeight > 0);
 
@@ -183,9 +185,9 @@ class SharedImage {
     }
   }
 
-  int32_t GetWidth() { return mWidth; }
+  int32_t GetWidth() const { return mWidth; }
 
-  int32_t GetHeight() { return mHeight; }
+  int32_t GetHeight() const { return mHeight; }
 
   SharedImage(const SharedImage&) = delete;
   SharedImage(SharedImage&&) = delete;
@@ -515,7 +517,7 @@ void Provider::HandleBorrowRequest(BorrowResponseData* aResponseData,
 
   aResponseData->result = ResponseResult::Error;
 
-  RECT clientRect = {};
+  RECT clientRect{};
   if (!::GetClientRect(mWindowHandle, &clientRect)) {
     return;
   }
@@ -523,12 +525,12 @@ void Provider::HandleBorrowRequest(BorrowResponseData* aResponseData,
   MOZ_ASSERT(clientRect.left == 0);
   MOZ_ASSERT(clientRect.top == 0);
 
-  int32_t width = clientRect.right ? clientRect.right : 1;
-  int32_t height = clientRect.bottom ? clientRect.bottom : 1;
+  const int32_t width = std::max(int32_t(clientRect.right), 1);
+  const int32_t height = std::max(int32_t(clientRect.bottom), 1);
 
   bool needNewBackbuffer = !aAllowSameBuffer || !mBackbuffer ||
-                           (mBackbuffer->GetWidth() != width) ||
-                           (mBackbuffer->GetHeight() != height);
+                           mBackbuffer->GetWidth() != width ||
+                           mBackbuffer->GetHeight() != height;
 
   if (!needNewBackbuffer) {
     aResponseData->result = ResponseResult::BorrowSameBuffer;
diff --git a/widget/windows/ToastNotification.cpp b/widget/windows/ToastNotification.cpp
index afdffc19ac..83692b26a1 100644
--- a/widget/windows/ToastNotification.cpp
+++ b/widget/windows/ToastNotification.cpp
@@ -776,6 +776,9 @@ ToastNotification::CloseAlert(const nsAString& aAlertName,
                               bool aContextClosed) {
   RefPtr<ToastNotificationHandler> handler;
   if (NS_WARN_IF(!mActiveHandlers.Get(aAlertName, getter_AddRefs(handler)))) {
+    // This can happen when the handler is gone but the closure signal is not
+    // yet reached to the content process, and then the process tries closing
+    // the same signal.
     return NS_OK;
   }
 
diff --git a/widget/windows/WinCompositorWidget.h b/widget/windows/WinCompositorWidget.h
index fef967380c..df5d443067 100644
--- a/widget/windows/WinCompositorWidget.h
+++ b/widget/windows/WinCompositorWidget.h
@@ -18,8 +18,7 @@
 
 class nsWindow;
 
-namespace mozilla {
-namespace widget {
+namespace mozilla::widget {
 
 class PlatformCompositorWidgetDelegate : public CompositorWidgetDelegate {
  public:
@@ -74,7 +73,7 @@ class WinCompositorWidget : public CompositorWidget {
   void UpdateCompositorWndSizeIfNecessary();
 
   void RequestFxrOutput();
-  bool HasFxrOutputHandler() const { return mFxrHandler != nullptr; }
+  bool HasFxrOutputHandler() const { return !!mFxrHandler; }
   FxROutputHandler* GetFxrOutputHandler() const { return mFxrHandler.get(); }
 
   virtual nsSizeMode GetWindowSizeMode() const = 0;
@@ -97,7 +96,6 @@ class WinCompositorWidget : public CompositorWidget {
   UniquePtr<FxROutputHandler> mFxrHandler;
 };
 
-}  // namespace widget
-}  // namespace mozilla
+}  // namespace mozilla::widget
 
 #endif  // widget_windows_WinCompositorWidget_h
diff --git a/widget/windows/filedialog/PWinFileDialog.ipdl b/widget/windows/filedialog/PWinFileDialog.ipdl
index 812db7e103..b61bfc0432 100644
--- a/widget/windows/filedialog/PWinFileDialog.ipdl
+++ b/widget/windows/filedialog/PWinFileDialog.ipdl
@@ -12,6 +12,16 @@ namespace mozilla {
 namespace widget {
 namespace filedialog {
 
+union FileResult {
+  Results?;
+  RemoteError;
+};
+
+union FolderResult {
+  nsString?;
+  RemoteError;
+};
+
 [ChildProc=Utility]
 protocol PWinFileDialog {
 
@@ -19,12 +29,13 @@ child:
   // Exactly one Show function should be called per instance. Further calls will
   // result in IPC failure.
   //
-  // Each will return `Nothing` iff the operation was canceled by the user.
+  // Each will return `Ok(Nothing)` if the operation was canceled by the user,
+  // or `Err(...)` if the operation actually failed.
 
   async ShowFileDialog(WindowsHandle parentHwnd, FileDialogType type, Command[] commands)
-    returns (Results? results);
+    returns (FileResult result);
   async ShowFolderDialog(WindowsHandle parentHwnd, Command[] commands)
-    returns (nsString? path);
+    returns (FolderResult result);
 };
 
 }  // namespace filedialog
diff --git a/widget/windows/filedialog/WinFileDialogChild.cpp b/widget/windows/filedialog/WinFileDialogChild.cpp
index a41018ff0e..ddb972534a 100644
--- a/widget/windows/filedialog/WinFileDialogChild.cpp
+++ b/widget/windows/filedialog/WinFileDialogChild.cpp
@@ -46,34 +46,23 @@ WinFileDialogChild::IPCResult WinFileDialogChild::MakeIpcFailure(
   return IPC_FAIL(this, what);
 }
 
-#define MOZ_IPC_ENSURE_HRESULT_OK(hr, what)             \
-  do {                                                  \
-    MOZ_LOG(sLogFileDialog, LogLevel::Verbose,          \
-            ("checking HRESULT for %s", what));         \
-    HRESULT const _hr_ = (hr);                          \
-    if (FAILED(_hr_)) {                                 \
-      MOZ_LOG(sLogFileDialog, LogLevel::Error,          \
-              ("HRESULT %8lX while %s", (hr), (what))); \
-      return MakeIpcFailure(_hr_, (what));              \
-    }                                                   \
-  } while (0)
-
 WinFileDialogChild::IPCResult WinFileDialogChild::RecvShowFileDialog(
     uintptr_t parentHwnd, FileDialogType type, nsTArray<Command> commands,
     FileResolver&& resolver) {
   MOZ_ABORT_IF_ALREADY_USED();
 
-  SpawnFilePicker(HWND(parentHwnd), type, std::move(commands))
-      ->Then(
-          GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
-          [resolver = std::move(resolver)](Maybe<Results> const& res) {
-            resolver(res);
-          },
-          [self = RefPtr(this)](HRESULT hr) {
-            // this doesn't need to be returned anywhere; it'll crash the
-            // process as a side effect of construction
-            self->MakeIpcFailure(hr, "SpawnFilePicker");
-          });
+  auto promise = SpawnFilePicker(HWND(parentHwnd), type, std::move(commands));
+  using RRV = std::decay_t<decltype(*promise)>::ResolveOrRejectValue;
+
+  promise->Then(GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+                [resolver = std::move(resolver)](RRV&& val) -> void {
+                  if (val.IsResolve()) {
+                    resolver(val.ResolveValue());
+                  } else {
+                    auto err = val.RejectValue();
+                    resolver(RemoteError(err.where.Serialize(), err.why));
+                  }
+                });
 
   return IPC_OK();
 }
@@ -83,23 +72,22 @@ WinFileDialogChild::IPCResult WinFileDialogChild::RecvShowFolderDialog(
     FolderResolver&& resolver) {
   MOZ_ABORT_IF_ALREADY_USED();
 
-  SpawnFolderPicker(HWND(parentHwnd), std::move(commands))
-      ->Then(
-          GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
-          [resolver = std::move(resolver)](Maybe<nsString> const& res) {
-            resolver(res);
-          },
-          [self = RefPtr(this), resolver](HRESULT hr) {
-            // this doesn't need to be returned anywhere; it'll crash the
-            // process as a side effect of construction
-            self->MakeIpcFailure(hr, "SpawnFolderPicker");
-          });
+  auto promise = SpawnFolderPicker(HWND(parentHwnd), std::move(commands));
+  using RRV = std::decay_t<decltype(*promise)>::ResolveOrRejectValue;
+
+  promise->Then(GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+                [resolver = std::move(resolver)](RRV&& val) -> void {
+                  if (val.IsResolve()) {
+                    resolver(val.ResolveValue());
+                  } else {
+                    auto err = val.RejectValue();
+                    resolver(RemoteError(err.where.Serialize(), err.why));
+                  }
+                });
 
   return IPC_OK();
 }
 
-#undef MOZ_IPC_ENSURE_HRESULT_OK
-
 void WinFileDialogChild::ProcessingError(Result aCode, const char* aReason) {
   detail::LogProcessingError(sLogFileDialog, this, aCode, aReason);
 }
diff --git a/widget/windows/filedialog/WinFileDialogCommands.cpp b/widget/windows/filedialog/WinFileDialogCommands.cpp
index 838856893d..75abbad343 100644
--- a/widget/windows/filedialog/WinFileDialogCommands.cpp
+++ b/widget/windows/filedialog/WinFileDialogCommands.cpp
@@ -22,6 +22,20 @@
 
 namespace mozilla::widget::filedialog {
 
+const char* Error::KindName(Error::Kind kind) {
+  switch (kind) {
+    case LocalError:
+      return "LocalError";
+    case RemoteError:
+      return "RemoteError";
+    case IPCError:
+      return "IPCError";
+    default:
+      MOZ_ASSERT(false);
+      return "<bad value>";
+  }
+}
+
 // Visitor to apply commands to the dialog.
 struct Applicator {
   IFileDialog* dialog = nullptr;
@@ -98,13 +112,15 @@ static HRESULT GetShellItemPath(IShellItem* aItem, nsString& aResultString) {
 }
 }  // namespace
 
-#define MOZ_ENSURE_HRESULT_OK(call_)            \
-  do {                                          \
-    HRESULT const _tmp_hr_ = (call_);           \
-    if (FAILED(_tmp_hr_)) return Err(_tmp_hr_); \
+#define MOZ_ENSURE_HRESULT_OK(where, call_)                     \
+  do {                                                          \
+    HRESULT const _tmp_hr_ = (call_);                           \
+    if (FAILED(_tmp_hr_)) {                                     \
+      return mozilla::Err(MOZ_FD_LOCAL_ERROR(where, _tmp_hr_)); \
+    }                                                           \
   } while (0)
 
-mozilla::Result<RefPtr<IFileDialog>, HRESULT> MakeFileDialog(
+mozilla::Result<RefPtr<IFileDialog>, Error> MakeFileDialog(
     FileDialogType type) {
   RefPtr<IFileDialog> dialog;
 
@@ -112,43 +128,45 @@ mozilla::Result<RefPtr<IFileDialog>, HRESULT> MakeFileDialog(
                                                    : CLSID_FileSaveDialog;
   HRESULT const hr = CoCreateInstance(clsid, nullptr, CLSCTX_INPROC_SERVER,
                                       IID_IFileDialog, getter_AddRefs(dialog));
-  MOZ_ENSURE_HRESULT_OK(hr);
+  // more properly: "CoCreateInstance(CLSID_...)", but this suffices
+  MOZ_ENSURE_HRESULT_OK("MakeFileDialog", hr);
 
   return std::move(dialog);
 }
 
-HRESULT ApplyCommands(::IFileDialog* dialog,
-                      nsTArray<Command> const& commands) {
+mozilla::Result<Ok, Error> ApplyCommands(::IFileDialog* dialog,
+                                         nsTArray<Command> const& commands) {
   Applicator applicator{.dialog = dialog};
   for (auto const& cmd : commands) {
     HRESULT const hr = applicator.Visit(cmd);
-    if (FAILED(hr)) {
-      return hr;
-    }
+    MOZ_ENSURE_HRESULT_OK("ApplyCommands", hr);
   }
-  return S_OK;
+  return Ok{};
 }
 
-mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog* dialog) {
+mozilla::Result<Results, Error> GetFileResults(::IFileDialog* dialog) {
   FILEOPENDIALOGOPTIONS fos;
-  MOZ_ENSURE_HRESULT_OK(dialog->GetOptions(&fos));
+  MOZ_ENSURE_HRESULT_OK("IFileDialog::GetOptions", dialog->GetOptions(&fos));
 
   using widget::WinUtils;
 
   // Extract which filter type the user selected
   UINT index;
-  MOZ_ENSURE_HRESULT_OK(dialog->GetFileTypeIndex(&index));
+  MOZ_ENSURE_HRESULT_OK("IFileDialog::GetFileTypeIndex",
+                        dialog->GetFileTypeIndex(&index));
 
   // single selection
   if ((fos & FOS_ALLOWMULTISELECT) == 0) {
     RefPtr<IShellItem> item;
-    MOZ_ENSURE_HRESULT_OK(dialog->GetResult(getter_AddRefs(item)));
+    MOZ_ENSURE_HRESULT_OK("IFileDialog::GetResult",
+                          dialog->GetResult(getter_AddRefs(item)));
     if (!item) {
-      return Err(E_FAIL);
+      return Err(MOZ_FD_LOCAL_ERROR("IFileDialog::GetResult: item", E_POINTER));
     }
 
     nsAutoString path;
-    MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, path));
+    MOZ_ENSURE_HRESULT_OK("GetFileResults: GetShellItemPath (1)",
+                          GetShellItemPath(item, path));
 
     return Results({path}, index);
   }
@@ -158,25 +176,29 @@ mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog* dialog) {
   dialog->QueryInterface(IID_IFileOpenDialog, getter_AddRefs(openDlg));
   if (!openDlg) {
     MOZ_ASSERT(false, "a file-save dialog was given FOS_ALLOWMULTISELECT?");
-    return Err(E_UNEXPECTED);
+    return Err(MOZ_FD_LOCAL_ERROR("Save + FOS_ALLOWMULTISELECT", E_UNEXPECTED));
   }
 
   RefPtr<IShellItemArray> items;
-  MOZ_ENSURE_HRESULT_OK(openDlg->GetResults(getter_AddRefs(items)));
+  MOZ_ENSURE_HRESULT_OK("IFileOpenDialog::GetResults",
+                        openDlg->GetResults(getter_AddRefs(items)));
   if (!items) {
-    return Err(E_FAIL);
+    return Err(
+        MOZ_FD_LOCAL_ERROR("IFileOpenDialog::GetResults: items", E_POINTER));
   }
 
   nsTArray<nsString> paths;
 
   DWORD count = 0;
-  MOZ_ENSURE_HRESULT_OK(items->GetCount(&count));
+  MOZ_ENSURE_HRESULT_OK("IShellItemArray::GetCount", items->GetCount(&count));
   for (DWORD idx = 0; idx < count; idx++) {
     RefPtr<IShellItem> item;
-    MOZ_ENSURE_HRESULT_OK(items->GetItemAt(idx, getter_AddRefs(item)));
+    MOZ_ENSURE_HRESULT_OK("IShellItemArray::GetItemAt",
+                          items->GetItemAt(idx, getter_AddRefs(item)));
 
     nsAutoString str;
-    MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, str));
+    MOZ_ENSURE_HRESULT_OK("GetFileResults: GetShellItemPath (2)",
+                          GetShellItemPath(item, str));
 
     paths.EmplaceBack(str);
   }
@@ -184,15 +206,17 @@ mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog* dialog) {
   return Results(std::move(paths), std::move(index));
 }
 
-mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog* dialog) {
+mozilla::Result<nsString, Error> GetFolderResults(::IFileDialog* dialog) {
   RefPtr<IShellItem> item;
-  MOZ_ENSURE_HRESULT_OK(dialog->GetResult(getter_AddRefs(item)));
+  MOZ_ENSURE_HRESULT_OK("IFileDialog::GetResult",
+                        dialog->GetResult(getter_AddRefs(item)));
+
   if (!item) {
     // shouldn't happen -- probably a precondition failure on our part, but
     // might be due to misbehaving shell extensions?
     MOZ_ASSERT(false,
                "unexpected lack of item: was `Show`'s return value checked?");
-    return Err(E_FAIL);
+    return Err(MOZ_FD_LOCAL_ERROR("IFileDialog::GetResult: item", E_POINTER));
   }
 
   // If the user chose a Win7 Library, resolve to the library's
@@ -200,6 +224,7 @@ mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog* dialog) {
   RefPtr<IShellLibrary> shellLib;
   RefPtr<IShellItem> folderPath;
   MOZ_ENSURE_HRESULT_OK(
+      "CoCreateInstance(CLSID_ShellLibrary)",
       CoCreateInstance(CLSID_ShellLibrary, nullptr, CLSCTX_INPROC_SERVER,
                        IID_IShellLibrary, getter_AddRefs(shellLib)));
 
@@ -211,7 +236,7 @@ mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog* dialog) {
 
   // get the folder's file system path
   nsAutoString str;
-  MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, str));
+  MOZ_ENSURE_HRESULT_OK("GetShellItemPath", GetShellItemPath(item, str));
   return str;
 }
 
@@ -312,12 +337,22 @@ void LogProcessingError(LogModule* aModule, ipc::IProtocol* aCaller,
 template <typename Res, typename Action, size_t N>
 RefPtr<Promise<Res>> SpawnFileDialogThread(const char (&where)[N],
                                            Action action) {
+  {
+    using ActionRetT = std::invoke_result_t<Action>;
+    using Info = detail::DestructureResult<ActionRetT>;
+
+    MOZ_ASSERT_SAME_TYPE(
+        typename Info::ErrorT, Error,
+        "supplied Action must return Result<T, filedialog::Err>");
+  }
+
   RefPtr<nsIThread> thread;
   {
     nsresult rv = NS_NewNamedThread("File Dialog", getter_AddRefs(thread),
                                     nullptr, {.isUiThread = true});
     if (NS_FAILED(rv)) {
-      return Promise<Res>::CreateAndReject((HRESULT)rv, where);
+      return Promise<Res>::CreateAndReject(
+          MOZ_FD_LOCAL_ERROR("NS_NewNamedThread", (HRESULT)rv), where);
     }
   }
   // `thread` is single-purpose, and should not perform any additional work
@@ -393,7 +428,7 @@ RefPtr<Promise<Res>> SpawnFileDialogThread(const char (&where)[N],
     }
 
     // Actually invoke the action and report the result.
-    Result<Res, HRESULT> val = action();
+    Result<Res, Error> val = action();
     if (val.isErr()) {
       promise->Reject(val.unwrapErr(), where);
     } else {
@@ -407,16 +442,16 @@ RefPtr<Promise<Res>> SpawnFileDialogThread(const char (&where)[N],
 // For F returning `Result<T, E>`, yields the type `T`.
 template <typename F, typename... Args>
 using inner_result_of =
-    typename std::remove_reference_t<decltype(std::declval<F>()(
-        std::declval<Args>()...))>::ok_type;
+    typename detail::DestructureResult<std::invoke_result_t<F, Args...>>::OkT;
 
 template <typename ExtractorF,
           typename RetT = inner_result_of<ExtractorF, IFileDialog*>>
 auto SpawnPickerT(HWND parent, FileDialogType type, ExtractorF&& extractor,
                   nsTArray<Command> commands) -> RefPtr<Promise<Maybe<RetT>>> {
+  using ActionRetT = Result<Maybe<RetT>, Error>;
+
   return detail::SpawnFileDialogThread<Maybe<RetT>>(
-      __PRETTY_FUNCTION__,
-      [=, commands = std::move(commands)]() -> Result<Maybe<RetT>, HRESULT> {
+      __PRETTY_FUNCTION__, [=, commands = std::move(commands)]() -> ActionRetT {
         // On Win10, the picker doesn't support per-monitor DPI, so we create it
         // with our context set temporarily to system-dpi-aware.
         WinUtils::AutoSystemDpiAware dpiAwareness;
@@ -424,15 +459,13 @@ auto SpawnPickerT(HWND parent, FileDialogType type, ExtractorF&& extractor,
         RefPtr<IFileDialog> dialog;
         MOZ_TRY_VAR(dialog, MakeFileDialog(type));
 
-        if (HRESULT const rv = ApplyCommands(dialog, commands); FAILED(rv)) {
-          return mozilla::Err(rv);
-        }
+        MOZ_TRY(ApplyCommands(dialog, commands));
 
         if (HRESULT const rv = dialog->Show(parent); FAILED(rv)) {
           if (rv == HRESULT_FROM_WIN32(ERROR_CANCELLED)) {
-            return Result<Maybe<RetT>, HRESULT>(Nothing());
+            return ActionRetT{Nothing()};
           }
-          return mozilla::Err(rv);
+          return mozilla::Err(MOZ_FD_LOCAL_ERROR("IFileDialog::Show", rv));
         }
 
         RetT res;
diff --git a/widget/windows/filedialog/WinFileDialogCommands.h b/widget/windows/filedialog/WinFileDialogCommands.h
index ca4561a8f2..800ce832d5 100644
--- a/widget/windows/filedialog/WinFileDialogCommands.h
+++ b/widget/windows/filedialog/WinFileDialogCommands.h
@@ -19,27 +19,200 @@ struct IFileOpenDialog;
 
 namespace mozilla::widget::filedialog {
 
+namespace detail {
+
+template <typename T, typename E, bool B>
+struct PromiseInfo {
+  using ResolveT = T;
+  using RejectT = E;
+  constexpr static const bool IsExclusive = B;
+  using Promise = MozPromise<T, E, B>;
+};
+
+template <typename P>
+auto DestructurePromiseImpl(P&&) {
+  // Debugging hint: A type in the instantiation chain (here named `P`) was
+  // expected to be a `RefPtr<MozPromise<...>>`, but was some other type.
+  static_assert(false, "expected P = RefPtr<MozPromise< ... >>");
+}
+
+template <typename T, typename E, bool B>
+auto DestructurePromiseImpl(RefPtr<MozPromise<T, E, B>>&&)
+    -> PromiseInfo<T, E, B>;
+
+template <typename P>
+using DestructurePromise =
+    std::decay_t<decltype(DestructurePromiseImpl(std::declval<P>()))>;
+
+template <typename T, typename E>
+struct ResultInfo {
+  using OkT = T;
+  using ErrorT = E;
+};
+
+template <typename R>
+auto DestructureResultImpl(R&&) {
+  // Debugging hint: A type in the instantiation chain (here named `R`) was
+  // expected to be a `mozilla::Result<...>`, but was some other type.
+  static_assert(false, "expected R = mozilla::Result< ... >");
+}
+
+template <typename T, typename E>
+auto DestructureResultImpl(mozilla::Result<T, E>&&) -> ResultInfo<T, E>;
+
+template <typename R>
+using DestructureResult =
+    std::decay_t<decltype(DestructureResultImpl(std::declval<R>()))>;
+
+#define MOZ_ASSERT_SAME_TYPE(T1, T2, ...) \
+  static_assert(std::is_same_v<T1, T2>, ##__VA_ARGS__)
+}  // namespace detail
+
 extern LazyLogModule sLogFileDialog;
 
+// Simple struct for reporting errors.
+struct Error {
+  enum Kind {
+    // This error's source was within the local (current) process.
+    LocalError,
+    // This error's source was within the remote host process, and it was
+    // reported via noncatastrophic channels.
+    RemoteError,
+    // This error was reported via the IPC subsystem. (This includes unexpected
+    // remote host-process crashes.)
+    IPCError,
+  };
+
+  // "Enum" denoting error-location. Members are in `VALID_STRINGS`, and have no
+  // name other than their string.
+  //
+  // (Note: under C++20, this could reasonably be replaced with an `nsString`
+  // alongside a check that all constructors are either a) consteval or b) from
+  // IPC.)
+  class Location {
+    uint32_t value;
+    constexpr explicit Location(uint32_t value) : value(value) {}
+
+    // Valid locations for errors. (Indices do not need to remain stable between
+    // releases; but -- where meaningful -- string values themselves should, for
+    // ease of telemetry-aggregation.)
+    constexpr static std::string_view const VALID_STRINGS[] = {
+        "ApplyCommands",
+        "CoCreateInstance(CLSID_ShellLibrary)",
+        "GetFileResults: GetShellItemPath (1)",
+        "GetFileResults: GetShellItemPath (2)",
+        "GetShellItemPath",
+        "IFileDialog::GetFileTypeIndex",
+        "IFileDialog::GetOptions",
+        "IFileDialog::GetResult",
+        "IFileDialog::GetResult: item",
+        "IFileDialog::Show",
+        "IFileOpenDialog::GetResults",
+        "IFileOpenDialog::GetResults: items",
+        "IPC",
+        "IShellItemArray::GetCount",
+        "IShellItemArray::GetItemAt",
+        "MakeFileDialog",
+        "NS_NewNamedThread",
+        "Save + FOS_ALLOWMULTISELECT",
+        "ShowFilePicker",
+        "ShowFolderPicker",
+        "ShowRemote: UtilityProcessManager::GetSingleton",
+        "ShowRemote: invocation of CreateWinFileDialogActor",
+        "UtilityProcessManager::CreateWinFileDialogActor",
+        "internal IPC failure?",
+    };
+    constexpr static size_t VALID_STRINGS_COUNT =
+        std::extent_v<decltype(VALID_STRINGS)>;
+
+    // Prevent duplicates from occurring in VALID_STRINGS by forcing it to be
+    // sorted. (Note that std::is_sorted is not constexpr until C++20.)
+    static_assert(
+        []() {
+          for (size_t i = 0; i + 1 < VALID_STRINGS_COUNT; ++i) {
+            if (!(VALID_STRINGS[i] < VALID_STRINGS[i + 1])) {
+              return false;
+            }
+          }
+          return true;
+        }(),
+        "VALID_STRINGS should be ASCIIbetically sorted");
+
+   public:
+    constexpr uint32_t Serialize() const { return value; }
+    constexpr static Location Deserialize(uint32_t val) {
+      return Location{val};
+    }
+
+   public:
+    constexpr static Location npos() { return Location{~uint32_t(0)}; }
+
+    constexpr bool IsValid() const { return value < VALID_STRINGS_COUNT; }
+
+    constexpr std::string_view ToString() const {
+      return value < VALID_STRINGS_COUNT ? VALID_STRINGS[value]
+                                         : "<bad filedialog::Error::Location?>";
+    }
+    constexpr static Location FromString(std::string_view str) {
+      for (uint32_t i = 0; i < VALID_STRINGS_COUNT; ++i) {
+        if (str == VALID_STRINGS[i]) return Location{i};
+      }
+      return npos();
+    }
+
+    constexpr char const* c_str() const { return ToString().data(); }
+  };
+
+  // Where and how (run-time) this error occurred.
+  Kind kind;
+  // Where (compile-time) this error occurred.
+  Location where;
+  // Why (run-time) this error occurred. Probably an HRESULT.
+  uint32_t why;
+
+  // `impl Debug for Kind`
+  static const char* KindName(Kind);
+};
+
+// Create a filedialog::Error, confirming at compile-time that the supplied
+// where-string is valid.
+#define MOZ_FD_ERROR(kind_, where_, why_)                                 \
+  ([](HRESULT why_arg_) -> ::mozilla::widget::filedialog::Error {         \
+    using Error = ::mozilla::widget::filedialog::Error;                   \
+    constexpr static const Error::Location loc =                          \
+        Error::Location::FromString(where_);                              \
+    static_assert(                                                        \
+        loc.IsValid(),                                                    \
+        "filedialog::Error: location not found in Error::VALID_STRINGS"); \
+    return Error{                                                         \
+        .kind = Error::kind_, .where = loc, .why = (uint32_t)why_arg_};   \
+  }(why_))
+
+// Create a filedialog::Error of kind LocalError (the usual case).
+#define MOZ_FD_LOCAL_ERROR(where_, why_) MOZ_FD_ERROR(LocalError, where_, why_)
+
+template <typename R>
+using Promise = MozPromise<R, Error, true>;
+
 enum class FileDialogType : uint8_t { Open, Save };
 
 // Create a file-dialog of the relevant type. Requires MSCOM to be initialized.
-mozilla::Result<RefPtr<IFileDialog>, HRESULT> MakeFileDialog(FileDialogType);
+mozilla::Result<RefPtr<IFileDialog>, Error> MakeFileDialog(FileDialogType);
 
 // Apply the selected commands to the IFileDialog, in preparation for showing
 // it. (The actual showing step is left to the caller.)
-[[nodiscard]] HRESULT ApplyCommands(::IFileDialog*,
-                                    nsTArray<Command> const& commands);
+mozilla::Result<Ok, Error> ApplyCommands(::IFileDialog*,
+                                         nsTArray<Command> const& commands);
 
 // Extract one or more results from the file-picker dialog.
 //
 // Requires that Show() has been called and has returned S_OK.
-mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog*);
+mozilla::Result<Results, Error> GetFileResults(::IFileDialog*);
 
 // Extract the chosen folder from the folder-picker dialog.
 //
 // Requires that Show() has been called and has returned S_OK.
-mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog*);
+mozilla::Result<nsString, Error> GetFolderResults(::IFileDialog*);
 
 namespace detail {
 // Log the error. If it's a notable error, kill the child process.
@@ -48,9 +221,6 @@ void LogProcessingError(LogModule* aModule, ipc::IProtocol* aCaller,
 
 }  // namespace detail
 
-template <typename R>
-using Promise = MozPromise<R, HRESULT, true>;
-
 // Show a file-picker on another thread in the current process.
 RefPtr<Promise<Maybe<Results>>> SpawnFilePicker(HWND parent,
                                                 FileDialogType type,
diff --git a/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh b/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh
index dd85942f24..352b46df17 100644
--- a/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh
+++ b/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh
@@ -44,6 +44,19 @@ struct Results {
   uint32_t selectedFileTypeIndex;
 };
 
+// Homolog of filedialog::Err. (Always Err::Kind::RemoteError, by definition.)
+struct RemoteError {
+  // An enum (`filedialog::Error::Location`) describing the compile-time location
+  // where the error was detected.
+  //
+  // (This value is validated at use-sites; if the child process sends a bad
+  // value, nothing of import will happen.)
+  uint32_t where;
+  // An error code describing the error itself more precisely. Its semantics
+  // depend on the context provided by `where`, but it's probably an HRESULT.
+  uint32_t why;
+};
+
 } // namespace filedialog
 } // namespace widget
 } // namespace mozilla
diff --git a/widget/windows/filedialog/WinFileDialogParent.cpp b/widget/windows/filedialog/WinFileDialogParent.cpp
index 2c256a1506..329c72cc94 100644
--- a/widget/windows/filedialog/WinFileDialogParent.cpp
+++ b/widget/windows/filedialog/WinFileDialogParent.cpp
@@ -54,6 +54,86 @@ PWinFileDialogParent::nsresult WinFileDialogParent::BindToUtilityProcess(
   return NS_OK;
 }
 
+// Convert the raw IPC promise-type to a filedialog::Promise.
+template <typename T, typename Ex, size_t N>
+static auto ConvertToFDPromise(
+    const char (&aMethod)[N],  // __func__
+    Ex&& extractor,
+    RefPtr<MozPromise<T, mozilla::ipc::ResponseRejectReason, true>>
+        aSrcPromise) {
+  // The extractor must produce a `mozilla::Result<..., Error>` from `T`.
+  using SrcResultInfo = detail::DestructureResult<std::invoke_result_t<Ex, T>>;
+  using ResolveT = typename SrcResultInfo::OkT;
+  static_assert(std::is_same_v<typename SrcResultInfo::ErrorT, Error>,
+                "expected T to be a Result<..., Error>");
+
+  using SrcPromiseT = MozPromise<T, mozilla::ipc::ResponseRejectReason, true>;
+  using DstPromiseT = MozPromise<ResolveT, Error, true>;
+
+  RefPtr<DstPromiseT> ret = aSrcPromise->Then(
+      mozilla::GetCurrentSerialEventTarget(), aMethod,
+
+      [extractor, aMethod](T&& val) {
+        mozilla::Result<ResolveT, Error> result = extractor(std::move(val));
+        if (result.isOk()) {
+          return DstPromiseT::CreateAndResolve(result.unwrap(), aMethod);
+        }
+        return DstPromiseT::CreateAndReject(result.unwrapErr(), aMethod);
+      },
+      [aMethod](typename mozilla::ipc::ResponseRejectReason&& val) {
+        return DstPromiseT::CreateAndReject(
+            MOZ_FD_ERROR(IPCError, "IPC", (uint32_t)val), aMethod);
+      });
+
+  return ret;
+}
+
+template <typename Input, typename Output>
+struct Extractor {
+  template <typename Input::Type tag_, Output const& (Input::*getter_)() const>
+  static auto get() {
+    return [](Input&& res) -> Result<Output, Error> {
+      if (res.type() == tag_) {
+        return (res.*getter_)();
+      }
+      if (res.type() == Input::TRemoteError) {
+        RemoteError err = res.get_RemoteError();
+        return Err(Error{.kind = Error::RemoteError,
+                         .where = Error::Location::Deserialize(err.where()),
+                         .why = err.why()});
+      }
+      MOZ_ASSERT_UNREACHABLE("internal IPC failure?");
+      return Err(MOZ_FD_ERROR(IPCError, "internal IPC failure?", E_FAIL));
+    };
+  }
+};
+
+[[nodiscard]] RefPtr<WinFileDialogParent::ShowFileDialogPromise>
+WinFileDialogParent::ShowFileDialogImpl(HWND parent, const FileDialogType& type,
+                                        mozilla::Span<Command const> commands) {
+  auto inner_promise = PWinFileDialogParent::SendShowFileDialog(
+      reinterpret_cast<WindowsHandle>(parent), type, std::move(commands));
+
+  return ConvertToFDPromise(
+      __func__,
+      Extractor<FileResult, Maybe<Results>>::get<
+          FileResult::TMaybeResults, &FileResult::get_MaybeResults>(),
+      std::move(inner_promise));
+}
+
+[[nodiscard]] RefPtr<WinFileDialogParent::ShowFolderDialogPromise>
+WinFileDialogParent::ShowFolderDialogImpl(
+    HWND parent, mozilla::Span<Command const> commands) {
+  auto inner_promise = PWinFileDialogParent::SendShowFolderDialog(
+      reinterpret_cast<WindowsHandle>(parent), std::move(commands));
+
+  return ConvertToFDPromise(
+      __func__,
+      Extractor<FolderResult, Maybe<nsString>>::get<
+          FolderResult::TMaybensString, &FolderResult::get_MaybensString>(),
+      std::move(inner_promise));
+}
+
 void WinFileDialogParent::ProcessingError(Result aCode, const char* aReason) {
   detail::LogProcessingError(sLogFileDialog, this, aCode, aReason);
 }
diff --git a/widget/windows/filedialog/WinFileDialogParent.h b/widget/windows/filedialog/WinFileDialogParent.h
index a2c1197c55..a1eb547444 100644
--- a/widget/windows/filedialog/WinFileDialogParent.h
+++ b/widget/windows/filedialog/WinFileDialogParent.h
@@ -21,11 +21,14 @@
 
 namespace mozilla::widget::filedialog {
 
-class WinFileDialogParent : public PWinFileDialogParent {
+class WinFileDialogParent final : private PWinFileDialogParent {
  public:
   using UtilityActorName = ::mozilla::UtilityActorName;
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinFileDialogParent, override);
 
+  using ShowFileDialogPromise = Promise<Maybe<Results>>;
+  using ShowFolderDialogPromise = Promise<Maybe<nsString>>;
+
  public:
   WinFileDialogParent();
   nsresult BindToUtilityProcess(
@@ -35,6 +38,16 @@ class WinFileDialogParent : public PWinFileDialogParent {
     return UtilityActorName::WindowsFileDialog;
   }
 
+  bool CanSend() const { return PWinFileDialogParent::CanSend(); }
+  void Close() { return PWinFileDialogParent::Close(); }
+
+  [[nodiscard]] RefPtr<ShowFileDialogPromise> ShowFileDialogImpl(
+      HWND parent, const FileDialogType& type,
+      mozilla::Span<Command const> commands);
+
+  [[nodiscard]] RefPtr<ShowFolderDialogPromise> ShowFolderDialogImpl(
+      HWND parent, mozilla::Span<Command const> commands);
+
  private:
   ~WinFileDialogParent();
 
diff --git a/widget/windows/nsDataObj.cpp b/widget/windows/nsDataObj.cpp
index 88a2a2ad09..60e2784f37 100644
--- a/widget/windows/nsDataObj.cpp
+++ b/widget/windows/nsDataObj.cpp
@@ -346,10 +346,10 @@ HRESULT nsDataObj::CreateStream(IStream** outStream) {
 
   pStream->AddRef();
 
-  // query the requestingPrincipal from the transferable and add it to the new
-  // channel
+  // query the dataPrincipal from the transferable and add it to the new
+  // channel.
   nsCOMPtr<nsIPrincipal> requestingPrincipal =
-      mTransferable->GetRequestingPrincipal();
+      mTransferable->GetDataPrincipal();
   MOZ_ASSERT(requestingPrincipal, "can not create channel without a principal");
 
   // Note that the cookieJarSettings could be null if the data object is for the
diff --git a/widget/windows/nsFilePicker.cpp b/widget/windows/nsFilePicker.cpp
index 2a45937988..89b10ce4ee 100644
--- a/widget/windows/nsFilePicker.cpp
+++ b/widget/windows/nsFilePicker.cpp
@@ -44,15 +44,17 @@
 #include "mozilla/widget/filedialog/WinFileDialogCommands.h"
 #include "mozilla/widget/filedialog/WinFileDialogParent.h"
 
+using mozilla::LogLevel;
 using mozilla::UniquePtr;
 
 using namespace mozilla::widget;
 
+template <typename Res>
+using FDPromise = filedialog::Promise<Res>;
+
 UniquePtr<char16_t[], nsFilePicker::FreeDeleter>
     nsFilePicker::sLastUsedUnicodeDirectory;
 
-using mozilla::LogLevel;
-
 #define MAX_EXTENSION_LENGTH 10
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -106,27 +108,29 @@ NS_IMETHODIMP nsFilePicker::Init(
 }
 
 namespace mozilla::detail {
+using Error = mozilla::widget::filedialog::Error;
+
 // Boilerplate for remotely showing a file dialog.
 template <typename ActionType,
           typename ReturnType = typename decltype(std::declval<ActionType>()(
               nullptr))::element_type::ResolveValueType>
-static auto ShowRemote(ActionType&& action)
-    -> RefPtr<MozPromise<ReturnType, HRESULT, true>> {
-  using RetPromise = MozPromise<ReturnType, HRESULT, true>;
+static auto ShowRemote(ActionType&& action) -> RefPtr<FDPromise<ReturnType>> {
+  using RetPromise = FDPromise<ReturnType>;
 
-  constexpr static const auto fail = []() {
-    return RetPromise::CreateAndReject(E_FAIL, __PRETTY_FUNCTION__);
-  };
+// "function-local" #define
+#define FAIL(where_, why_)                                             \
+  return RetPromise::CreateAndReject(MOZ_FD_LOCAL_ERROR(where_, why_), \
+                                     __PRETTY_FUNCTION__)
 
   auto mgr = mozilla::ipc::UtilityProcessManager::GetSingleton();
   if (!mgr) {
     MOZ_ASSERT(false);
-    return fail();
+    FAIL("ShowRemote: UtilityProcessManager::GetSingleton", E_POINTER);
   }
 
   auto wfda = mgr->CreateWinFileDialogActor();
   if (!wfda) {
-    return fail();
+    FAIL("ShowRemote: invocation of CreateWinFileDialogActor", E_POINTER);
   }
 
   using mozilla::widget::filedialog::sLogFileDialog;
@@ -135,32 +139,70 @@ static auto ShowRemote(ActionType&& action)
       mozilla::GetMainThreadSerialEventTarget(),
       "nsFilePicker ShowRemote acquire",
       [action = std::forward<ActionType>(action)](
-          filedialog::ProcessProxy const& p) -> RefPtr<RetPromise> {
+          filedialog::ProcessProxy p) -> RefPtr<RetPromise> {
         MOZ_LOG(sLogFileDialog, LogLevel::Info,
                 ("nsFilePicker ShowRemote first callback: p = [%p]", p.get()));
 
         // false positive: not actually redundant
         // NOLINTNEXTLINE(readability-redundant-smartptr-get)
-        return action(p.get())->Then(
-            mozilla::GetMainThreadSerialEventTarget(),
-            "nsFilePicker ShowRemote call",
-            [p](ReturnType ret) {
-              return RetPromise::CreateAndResolve(std::move(ret),
-                                                  __PRETTY_FUNCTION__);
-            },
-            [](mozilla::ipc::ResponseRejectReason error) {
-              MOZ_LOG(sLogFileDialog, LogLevel::Error,
-                      ("IPC call rejected: %zu", size_t(error)));
-              return fail();
+        auto promise = action(p.get());
+        return promise->Map(
+            mozilla::GetMainThreadSerialEventTarget(), __func__,
+            [p = std::move(p)](typename RetPromise::ResolveValueType&& val) {
+              // explicitly retain the ProcessProxy until at least this point
+              return std::move(val);
             });
       },
       [](nsresult error) -> RefPtr<RetPromise> {
         MOZ_LOG(sLogFileDialog, LogLevel::Error,
                 ("could not acquire WinFileDialog: %zu", size_t(error)));
-        return fail();
+        // TODO: pipe more data up from utility-process creation
+        FAIL("UtilityProcessManager::CreateWinFileDialogActor",
+             (uint32_t)error);
+      });
+
+#undef FAIL
+}
+
+namespace {
+
+static RefPtr<FDPromise<Maybe<filedialog::Results>>> ShowFilePickerRemote(
+    HWND parent, filedialog::FileDialogType type,
+    nsTArray<filedialog::Command> const& commands) {
+  using mozilla::widget::filedialog::sLogFileDialog;
+  return mozilla::detail::ShowRemote(
+      [parent, type,
+       commands = commands.Clone()](filedialog::WinFileDialogParent* p) {
+        MOZ_LOG(sLogFileDialog, LogLevel::Info,
+                ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
+        return p->ShowFileDialogImpl(parent, type, commands);
       });
 }
 
+static RefPtr<FDPromise<Maybe<nsString>>> ShowFolderPickerRemote(
+    HWND parent, nsTArray<filedialog::Command> const& commands) {
+  using mozilla::widget::filedialog::sLogFileDialog;
+  return mozilla::detail::ShowRemote([parent, commands = commands.Clone()](
+                                         filedialog::WinFileDialogParent* p) {
+    MOZ_LOG(sLogFileDialog, LogLevel::Info,
+            ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
+    return p->ShowFolderDialogImpl(parent, commands);
+  });
+}
+
+static RefPtr<FDPromise<Maybe<filedialog::Results>>> ShowFilePickerLocal(
+    HWND parent, filedialog::FileDialogType type,
+    nsTArray<filedialog::Command> const& commands) {
+  return filedialog::SpawnFilePicker(parent, type, commands.Clone());
+}
+
+static RefPtr<FDPromise<Maybe<nsString>>> ShowFolderPickerLocal(
+    HWND parent, nsTArray<filedialog::Command> const& commands) {
+  return filedialog::SpawnFolderPicker(parent, commands.Clone());
+}
+
+}  // namespace
+
 // fd_async
 //
 // Wrapper-namespace for the AsyncExecute() and AsyncAll() functions.
@@ -296,31 +338,83 @@ static void RecordFailure(uint64_t (&&time)[3], HRESULT hrRemote,
 }
 
 }  // namespace telemetry
+
+/* N.B.: L and R stand for Local and Remote, not just Left and Right */
+template <typename FnL, typename FnR, typename... Args>
+struct AsyncExecuteInfo {
+  template <typename T>
+  using DestructurePromise = widget::filedialog::detail::DestructurePromise<T>;
+
+  using Unit = ::mozilla::Ok;
+
+  using RetL = std::invoke_result_t<FnL, Args...>;
+  using RetR = std::invoke_result_t<FnR, Args...>;
+
+  using InfoL = DestructurePromise<RetL>;
+  using InfoR = DestructurePromise<RetR>;
+
+  MOZ_ASSERT_SAME_TYPE(
+      typename InfoL::ResolveT, typename InfoR::ResolveT,
+      "local and remote promises must have identical resolve-types");
+
+  // At present, the local and remote promises have the same type, but this
+  // isn't logically necessary. (In particular, a future refactor may remove the
+  // redundant `.kind` from the local promises' return types.)
+  MOZ_ASSERT_SAME_TYPE(typename InfoL::RejectT, filedialog::Error,
+                       "local promise must reject with a filedialog::Error");
+
+  MOZ_ASSERT_SAME_TYPE(typename InfoR::RejectT, filedialog::Error,
+                       "remote promise must reject with a filedialog::Error");
+
+  using ResolveT = typename InfoL::ResolveT;
+  using PromiseT = MozPromise<ResolveT, Unit, true>;
+
+  using RetT = RefPtr<PromiseT>;
+};
+
 }  // namespace details
 
-// Invoke either or both of a "do locally" and "do remotely" function with the
-// provided arguments, depending on the relevant preference-value and whether
-// or not the remote version fails.
+// Invoke either or both of a promise-returning "do locally" and "do remotely"
+// function with the provided arguments, depending on the relevant preference's
+// value and on whether or not the remote version fails (returns a rejection-
+// promise).
 //
-// Both functions must be asynchronous, returning a `RefPtr<MozPromise<...>>`.
-// "Failure" is defined as the promise being rejected.
+// Both provided functions must return a `RefPtr<filedialog::MozPromise<T>>`. As
+// `AsyncExecute` reports failures itself, its rejection-type is `()`.
 template <typename Fn1, typename Fn2, typename... Args>
-static auto AsyncExecute(Fn1 local, Fn2 remote, Args const&... args)
-    -> std::invoke_result_t<Fn1, Args...> {
+static auto AsyncExecute(Fn1 local, Fn2 remote, Args const&... args) ->
+    typename details::AsyncExecuteInfo<Fn1, Fn2, Args...>::RetT {
   using namespace details;
+  using Info = AsyncExecuteInfo<Fn1, Fn2, Args...>;
 
-  static_assert(std::is_same_v<std::invoke_result_t<Fn1, Args...>,
-                               std::invoke_result_t<Fn2, Args...>>);
-  using PromiseT = typename std::invoke_result_t<Fn1, Args...>::element_type;
+  using ResolveT = typename Info::ResolveT;
+  using PromiseT = typename Info::PromiseT;
+  using LPromiseT = typename Info::InfoL::Promise;
+  using RPromiseT = typename Info::InfoR::Promise;
 
   constexpr static char kFunctionName[] = "LocalAndOrRemote::AsyncExecute";
 
   switch (GetStrategy()) {
-    case Local:
-      return local(args...);
+    case Local: {
+      return local(args...)->MapErr(
+          NS_GetCurrentThread(), __func__, [](Error const& err) {
+            MOZ_ASSERT(err.kind == Error::LocalError);
+            MOZ_LOG(filedialog::sLogFileDialog, LogLevel::Info,
+                    ("local file-dialog failed: where=%s, why=%08" PRIX32,
+                     err.where.c_str(), err.why));
+            return Ok();
+          });
+    }
 
     case Remote:
-      return remote(args...);
+      return remote(args...)->MapErr(
+          NS_GetCurrentThread(), __func__, [](Error const& err) {
+            MOZ_LOG(
+                filedialog::sLogFileDialog, LogLevel::Info,
+                ("remote file-dialog failed: kind=%s, where=%s, why=%08" PRIX32,
+                 Error::KindName(err.kind), err.where.c_str(), err.why));
+            return Ok();
+          });
 
     case RemoteWithFallback:
       // more complicated; continue below
@@ -337,34 +431,40 @@ static auto AsyncExecute(Fn1 local, Fn2 remote, Args const&... args)
 
   return remote(args...)->Then(
       NS_GetCurrentThread(), kFunctionName,
-      [t0](typename PromiseT::ResolveValueType result) -> RefPtr<PromiseT> {
+      [t0](typename RPromiseT::ResolveValueType result) -> RefPtr<PromiseT> {
         // success; stop here
         auto const t1 = GetTime();
         // record success
         telemetry::RecordSuccess({t0, t1});
-        return PromiseT::CreateAndResolve(result, kFunctionName);
+        return PromiseT::CreateAndResolve(std::move(result), kFunctionName);
       },
       // initialized lambda pack captures are C++20 (clang 9, gcc 9);
       // `make_tuple` is just a C++17 workaround
       [=, tuple = std::make_tuple(Copy(args)...)](
-          typename PromiseT::RejectValueType err) mutable -> RefPtr<PromiseT> {
+          typename RPromiseT::RejectValueType err) mutable -> RefPtr<PromiseT> {
         // failure; record time
         auto const t1 = GetTime();
-        HRESULT const hrRemote = err;
+        // TODO: also propagate `err.where` into telemetry
+        HRESULT const hrRemote = err.why;
 
         // retry locally...
         auto p0 = std::apply(local, std::move(tuple));
         // ...then record the telemetry event
         return p0->Then(
             NS_GetCurrentThread(), kFunctionName,
-            [t0, t1,
-             hrRemote](typename PromiseT::ResolveOrRejectValue const& val)
+            [t0, t1, hrRemote](typename LPromiseT::ResolveOrRejectValue&& val)
                 -> RefPtr<PromiseT> {
               auto const t2 = GetTime();
-              HRESULT const hrLocal = val.IsReject() ? val.RejectValue() : S_OK;
+              HRESULT const hrLocal =
+                  val.IsReject() ? (HRESULT)val.RejectValue().why : S_OK;
               telemetry::RecordFailure({t0, t1, t2}, hrRemote, hrLocal);
 
-              return PromiseT::CreateAndResolveOrReject(val, kFunctionName);
+              using V = typename PromiseT::ResolveOrRejectValue;
+              return PromiseT::CreateAndResolveOrReject(
+                  val.IsResolve()
+                      ? V::MakeResolve(std::move(val).ResolveValue())
+                      : V::MakeReject(Ok{}),
+                  kFunctionName);
             });
       });
 }
@@ -393,45 +493,6 @@ using fd_async::AsyncExecute;
 
 }  // namespace mozilla::detail
 
-/* static */
-nsFilePicker::FPPromise<filedialog::Results> nsFilePicker::ShowFilePickerRemote(
-    HWND parent, filedialog::FileDialogType type,
-    nsTArray<filedialog::Command> const& commands) {
-  using mozilla::widget::filedialog::sLogFileDialog;
-  return mozilla::detail::ShowRemote(
-      [parent, type,
-       commands = commands.Clone()](filedialog::WinFileDialogParent* p) {
-        MOZ_LOG(sLogFileDialog, LogLevel::Info,
-                ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
-        return p->SendShowFileDialog((uintptr_t)parent, type, commands);
-      });
-}
-
-/* static */
-nsFilePicker::FPPromise<nsString> nsFilePicker::ShowFolderPickerRemote(
-    HWND parent, nsTArray<filedialog::Command> const& commands) {
-  using mozilla::widget::filedialog::sLogFileDialog;
-  return mozilla::detail::ShowRemote([parent, commands = commands.Clone()](
-                                         filedialog::WinFileDialogParent* p) {
-    MOZ_LOG(sLogFileDialog, LogLevel::Info,
-            ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
-    return p->SendShowFolderDialog((uintptr_t)parent, commands);
-  });
-}
-
-/* static */
-nsFilePicker::FPPromise<filedialog::Results> nsFilePicker::ShowFilePickerLocal(
-    HWND parent, filedialog::FileDialogType type,
-    nsTArray<filedialog::Command> const& commands) {
-  return filedialog::SpawnFilePicker(parent, type, commands.Clone());
-}
-
-/* static */
-nsFilePicker::FPPromise<nsString> nsFilePicker::ShowFolderPickerLocal(
-    HWND parent, nsTArray<filedialog::Command> const& commands) {
-  return filedialog::SpawnFolderPicker(parent, commands.Clone());
-}
-
 /*
  * Folder picker invocation
  */
@@ -447,16 +508,8 @@ nsFilePicker::FPPromise<nsString> nsFilePicker::ShowFolderPickerLocal(
  *          - resolves to false if the dialog was cancelled by the user;
  *          - is rejected with the associated HRESULT if some error occurred.
  */
-RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFolderPicker(
-    const nsString& aInitialDir) {
-  using Promise = mozilla::MozPromise<bool, HRESULT, true>;
-  constexpr static auto Ok = [](bool val) {
-    return Promise::CreateAndResolve(val, "nsFilePicker::ShowFolderPicker");
-  };
-  constexpr static auto NotOk = [](HRESULT val = E_FAIL) {
-    return Promise::CreateAndReject(val, "nsFilePicker::ShowFolderPicker");
-  };
-
+RefPtr<mozilla::MozPromise<bool, nsFilePicker::Unit, true>>
+nsFilePicker::ShowFolderPicker(const nsString& aInitialDir) {
   namespace fd = ::mozilla::widget::filedialog;
   nsTArray<fd::Command> commands = {
       fd::SetOptions(FOS_PICKFOLDERS),
@@ -474,23 +527,18 @@ RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFolderPicker(
   ScopedRtlShimWindow shim(mParentWidget.get());
   AutoWidgetPickerState awps(mParentWidget);
 
-  return mozilla::detail::AsyncExecute(&ShowFolderPickerLocal,
-                                       &ShowFolderPickerRemote, shim.get(),
-                                       commands)
-      ->Then(
-          NS_GetCurrentThread(), __PRETTY_FUNCTION__,
-          [self = RefPtr(this), shim = std::move(shim),
-           awps = std::move(awps)](Maybe<nsString> val) {
-            if (val) {
-              self->mUnicodeFile = val.extract();
-              return Ok(true);
-            }
-            return Ok(false);
-          },
-          [](HRESULT err) {
-            NS_WARNING("ShowFolderPicker failed");
-            return NotOk(err);
-          });
+  return mozilla::detail::AsyncExecute(&mozilla::detail::ShowFolderPickerLocal,
+                                       &mozilla::detail::ShowFolderPickerRemote,
+                                       shim.get(), commands)
+      ->Map(NS_GetCurrentThread(), __PRETTY_FUNCTION__,
+            [self = RefPtr(this), shim = std::move(shim),
+             awps = std::move(awps)](Maybe<nsString> val) {
+              if (val) {
+                self->mUnicodeFile = val.extract();
+                return true;
+              }
+              return false;
+            });
 }
 
 /*
@@ -508,16 +556,16 @@ RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFolderPicker(
  *          - resolves to false if the dialog was cancelled by the user;
  *          - is rejected with the associated HRESULT if some error occurred.
  */
-RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFilePicker(
-    const nsString& aInitialDir) {
+RefPtr<mozilla::MozPromise<bool, nsFilePicker::Unit, true>>
+nsFilePicker::ShowFilePicker(const nsString& aInitialDir) {
   AUTO_PROFILER_LABEL("nsFilePicker::ShowFilePicker", OTHER);
 
-  using Promise = mozilla::MozPromise<bool, HRESULT, true>;
+  using Promise = mozilla::MozPromise<bool, Unit, true>;
   constexpr static auto Ok = [](bool val) {
     return Promise::CreateAndResolve(val, "nsFilePicker::ShowFilePicker");
   };
-  constexpr static auto NotOk = [](HRESULT val = E_FAIL) {
-    return Promise::CreateAndReject(val, "nsFilePicker::ShowFilePicker");
+  constexpr static auto NotOk = []() {
+    return Promise::CreateAndReject(Unit(), "nsFilePicker::ShowFilePicker");
   };
 
   namespace fd = ::mozilla::widget::filedialog;
@@ -551,7 +599,7 @@ RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFilePicker(
 
       case modeGetFolder:
         MOZ_ASSERT(false, "file-picker opened in directory-picker mode");
-        return NotOk(E_FAIL);
+        return NotOk();
     }
 
     commands.AppendElement(fd::SetOptions(fos));
@@ -605,7 +653,8 @@ RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFilePicker(
   auto type = mMode == modeSave ? FileDialogType::Save : FileDialogType::Open;
 
   auto promise = mozilla::detail::AsyncExecute(
-      &ShowFilePickerLocal, &ShowFilePickerRemote, shim.get(), type, commands);
+      &mozilla::detail::ShowFilePickerLocal,
+      &mozilla::detail::ShowFilePickerRemote, shim.get(), type, commands);
 
   return promise->Then(
       mozilla::GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
@@ -641,9 +690,9 @@ RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFilePicker(
 
         return Ok(true);
       },
-      [](HRESULT err) {
+      [](Unit err) {
         NS_WARNING("ShowFilePicker failed");
-        return NotOk(err);
+        return NotOk();
       });
 }
 
@@ -752,43 +801,29 @@ nsFilePicker::CheckContentAnalysisService() {
     return promise;
   };
 
-  // Since getting the files to analyze might be asynchronous, use a MozPromise
-  // to unify the logic below.
-  auto getFilesToAnalyzePromise = mozilla::MakeRefPtr<mozilla::MozPromise<
-      nsTArray<mozilla::PathString>, nsresult, true>::Private>(__func__);
+  nsCOMArray<nsIFile> files;
   if (mMode == modeGetFolder) {
-    nsCOMPtr<nsISupports> tmp;
-    nsresult rv = GetDomFileOrDirectory(getter_AddRefs(tmp));
+    nsCOMPtr<nsIFile> file;
+    nsresult rv = GetFile(getter_AddRefs(file));
     if (NS_WARN_IF(NS_FAILED(rv))) {
-      getFilesToAnalyzePromise->Reject(rv, __func__);
       return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
                                                                     __func__);
     }
-    auto* directory = static_cast<mozilla::dom::Directory*>(tmp.get());
-    mozilla::dom::OwningFileOrDirectory owningDirectory;
-    owningDirectory.SetAsDirectory() = directory;
-    nsTArray<mozilla::dom::OwningFileOrDirectory> directoryArray{
-        std::move(owningDirectory)};
-
-    mozilla::ErrorResult error;
-    RefPtr<mozilla::dom::GetFilesHelper> helper =
-        mozilla::dom::GetFilesHelper::Create(directoryArray, true, error);
-    rv = error.StealNSResult();
+    nsCOMPtr<nsIDirectoryEnumerator> iter;
+    rv = file->GetDirectoryEntries(getter_AddRefs(iter));
     if (NS_WARN_IF(NS_FAILED(rv))) {
-      getFilesToAnalyzePromise->Reject(rv, __func__);
       return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
                                                                     __func__);
     }
-    auto getFilesCallback = mozilla::MakeRefPtr<GetFilesInDirectoryCallback>(
-        getFilesToAnalyzePromise);
-    helper->AddCallback(getFilesCallback);
+    nsCOMPtr<nsIFile> entry;
+    while (NS_SUCCEEDED(iter->GetNextFile(getter_AddRefs(entry))) && entry) {
+      files.AppendElement(entry);
+    }
   } else {
-    nsCOMArray<nsIFile> files;
     if (!mUnicodeFile.IsEmpty()) {
       nsCOMPtr<nsIFile> file;
       rv = GetFile(getter_AddRefs(file));
       if (NS_WARN_IF(NS_FAILED(rv))) {
-        getFilesToAnalyzePromise->Reject(rv, __func__);
         return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
                                                                       __func__);
       }
@@ -796,22 +831,13 @@ nsFilePicker::CheckContentAnalysisService() {
     } else {
       files.AppendElements(mFiles);
     }
-    nsTArray<mozilla::PathString> paths(files.Length());
-    std::transform(files.begin(), files.end(), MakeBackInserter(paths),
-                   [](auto* entry) { return entry->NativePath(); });
-    getFilesToAnalyzePromise->Resolve(std::move(paths), __func__);
   }
+  nsTArray<mozilla::PathString> paths(files.Length());
+  std::transform(files.begin(), files.end(), MakeBackInserter(paths),
+                 [](auto* entry) { return entry->NativePath(); });
 
-  return getFilesToAnalyzePromise->Then(
-      mozilla::GetMainThreadSerialEventTarget(), __func__,
-      [processOneItem](nsTArray<mozilla::PathString> aPaths) mutable {
-        return mozilla::detail::AsyncAll<mozilla::PathString>(std::move(aPaths),
-                                                              processOneItem);
-      },
-      [](nsresult aError) {
-        return nsFilePicker::ContentAnalysisResponse::CreateAndReject(aError,
-                                                                      __func__);
-      });
+  return mozilla::detail::AsyncAll<mozilla::PathString>(std::move(paths),
+                                                        processOneItem);
 };
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -891,10 +917,8 @@ nsresult nsFilePicker::Open(nsIFilePickerShownCallback* aCallback) {
 
         callback->Done(retValue);
       },
-      [callback = RefPtr(aCallback)](HRESULT err) {
-        using mozilla::widget::filedialog::sLogFileDialog;
-        MOZ_LOG(sLogFileDialog, LogLevel::Error,
-                ("nsFilePicker: Show failed with hr=0x%08lX", err));
+      [callback = RefPtr(aCallback)](Unit _) {
+        // logging already handled
         callback->Done(ResultCode::returnCancel);
       });
 
diff --git a/widget/windows/nsFilePicker.h b/widget/windows/nsFilePicker.h
index 59108bc0dd..5a4272d30f 100644
--- a/widget/windows/nsFilePicker.h
+++ b/widget/windows/nsFilePicker.h
@@ -56,8 +56,6 @@ class nsFilePicker final : public nsBaseWinFilePicker {
   using Maybe = mozilla::Maybe<T>;
   template <typename T>
   using Result = mozilla::Result<T, HRESULT>;
-  template <typename Res>
-  using FPPromise = RefPtr<mozilla::MozPromise<Maybe<Res>, HRESULT, true>>;
 
   using Command = mozilla::widget::filedialog::Command;
   using Results = mozilla::widget::filedialog::Results;
@@ -89,23 +87,12 @@ class nsFilePicker final : public nsBaseWinFilePicker {
   NS_IMETHOD Open(nsIFilePickerShownCallback* aCallback) override;
 
  private:
-  RefPtr<mozilla::MozPromise<bool, HRESULT, true>> ShowFolderPicker(
+  using Unit = mozilla::Ok;
+  RefPtr<mozilla::MozPromise<bool, Unit, true>> ShowFolderPicker(
       const nsString& aInitialDir);
-  RefPtr<mozilla::MozPromise<bool, HRESULT, true>> ShowFilePicker(
+  RefPtr<mozilla::MozPromise<bool, Unit, true>> ShowFilePicker(
       const nsString& aInitialDir);
 
-  // Show the dialog out-of-process.
-  static FPPromise<Results> ShowFilePickerRemote(
-      HWND aParent, FileDialogType type, nsTArray<Command> const& commands);
-  static FPPromise<nsString> ShowFolderPickerRemote(
-      HWND aParent, nsTArray<Command> const& commands);
-
-  // Show the dialog in-process.
-  static FPPromise<Results> ShowFilePickerLocal(
-      HWND aParent, FileDialogType type, nsTArray<Command> const& commands);
-  static FPPromise<nsString> ShowFolderPickerLocal(
-      HWND aParent, nsTArray<Command> const& commands);
-
   void ClearFiles();
   using ContentAnalysisResponse = mozilla::MozPromise<bool, nsresult, true>;
   RefPtr<ContentAnalysisResponse> CheckContentAnalysisService();
diff --git a/widget/windows/nsNativeThemeWin.cpp b/widget/windows/nsNativeThemeWin.cpp
index 7ef968baf6..b988fb4ec5 100644
--- a/widget/windows/nsNativeThemeWin.cpp
+++ b/widget/windows/nsNativeThemeWin.cpp
@@ -481,6 +481,7 @@ mozilla::Maybe<nsUXThemeClass> nsNativeThemeWin::GetThemeClass(
     case StyleAppearance::Button:
       return Some(eUXButton);
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
       return Some(eUXEdit);
@@ -500,12 +501,7 @@ mozilla::Maybe<nsUXThemeClass> nsNativeThemeWin::GetThemeClass(
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
       return Some(eUXCombobox);
-    case StyleAppearance::Treeheadercell:
-      return Some(eUXHeader);
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
-    case StyleAppearance::Treetwistyopen:
-    case StyleAppearance::Treeitem:
       return Some(eUXListview);
     default:
       return Nothing();
@@ -594,6 +590,7 @@ nsresult nsNativeThemeWin::GetThemePartAndState(nsIFrame* aFrame,
       return NS_OK;
     }
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea: {
       ElementState elementState = GetContentState(aFrame, aAppearance);
@@ -716,7 +713,6 @@ nsresult nsNativeThemeWin::GetThemePartAndState(nsIFrame* aFrame,
       }
       return NS_OK;
     }
-    case StyleAppearance::Treeview:
     case StyleAppearance::Listbox: {
       aPart = TREEVIEW_BODY;
       aState = TS_NORMAL;
@@ -753,17 +749,6 @@ nsresult nsNativeThemeWin::GetThemePartAndState(nsIFrame* aFrame,
 
       return NS_OK;
     }
-    case StyleAppearance::Treeheadercell: {
-      aPart = 1;
-      if (!aFrame) {
-        aState = TS_NORMAL;
-        return NS_OK;
-      }
-
-      aState = StandardGetState(aFrame, aAppearance, true);
-
-      return NS_OK;
-    }
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Menulist: {
       nsIContent* content = aFrame->GetContent();
@@ -956,6 +941,7 @@ RENDER_AGAIN:
 
     DrawThemeBackground(theme, hdc, part, state, &contentRect, &clipRect);
   } else if (aAppearance == StyleAppearance::NumberInput ||
+             aAppearance == StyleAppearance::PasswordInput ||
              aAppearance == StyleAppearance::Textfield ||
              aAppearance == StyleAppearance::Textarea) {
     DrawThemeBackground(theme, hdc, part, state, &widgetRect, &clipRect);
@@ -1088,6 +1074,7 @@ LayoutDeviceIntMargin nsNativeThemeWin::GetWidgetBorder(
   }
 
   if (aFrame && (aAppearance == StyleAppearance::NumberInput ||
+                 aAppearance == StyleAppearance::PasswordInput ||
                  aAppearance == StyleAppearance::Textfield ||
                  aAppearance == StyleAppearance::Textarea)) {
     nsIContent* content = aFrame->GetContent();
@@ -1128,6 +1115,7 @@ bool nsNativeThemeWin::GetWidgetPadding(nsDeviceContext* aContext,
    * added, see bug 430212)
    */
   if (aAppearance == StyleAppearance::NumberInput ||
+      aAppearance == StyleAppearance::PasswordInput ||
       aAppearance == StyleAppearance::Textfield ||
       aAppearance == StyleAppearance::Textarea) {
     aResult->top = aResult->bottom = 2;
@@ -1236,12 +1224,12 @@ LayoutDeviceIntSize nsNativeThemeWin::GetMinimumWidgetSize(
 
   switch (aAppearance) {
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Progresschunk:
     case StyleAppearance::Tabpanels:
     case StyleAppearance::Tabpanel:
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
       return {};  // Don't worry about it.
     default:
       break;
@@ -1386,6 +1374,7 @@ bool nsNativeThemeWin::ThemeDrawsFocusForWidget(nsIFrame* aFrame,
     case StyleAppearance::Textarea:
     case StyleAppearance::Textfield:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
       return true;
     default:
       return false;
@@ -1438,6 +1427,7 @@ bool nsNativeThemeWin::ClassicThemeSupportsWidget(nsIFrame* aFrame,
   switch (aAppearance) {
     case StyleAppearance::Button:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Range:
@@ -1445,7 +1435,6 @@ bool nsNativeThemeWin::ClassicThemeSupportsWidget(nsIFrame* aFrame,
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
     case StyleAppearance::ProgressBar:
     case StyleAppearance::Progresschunk:
     case StyleAppearance::Tab:
@@ -1465,11 +1454,11 @@ LayoutDeviceIntMargin nsNativeThemeWin::ClassicGetWidgetBorder(
       result.top = result.left = result.bottom = result.right = 2;
       break;
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
     case StyleAppearance::Menulist:
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Tab:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
       result.top = result.left = result.bottom = result.right = 2;
@@ -1516,8 +1505,8 @@ LayoutDeviceIntSize nsNativeThemeWin::ClassicGetMinimumWidgetSize(
     case StyleAppearance::MenulistButton:
     case StyleAppearance::Button:
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Progresschunk:
@@ -1574,8 +1563,8 @@ nsresult nsNativeThemeWin::ClassicGetThemePartAndState(
       return NS_OK;
     }
     case StyleAppearance::Listbox:
-    case StyleAppearance::Treeview:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Menulist:
@@ -1767,6 +1756,7 @@ RENDER_AGAIN:
     }
     // Draw controls with 2px 3D inset border
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Listbox:
@@ -1787,15 +1777,6 @@ RENDER_AGAIN:
 
       break;
     }
-    case StyleAppearance::Treeview: {
-      // Draw inset edge
-      ::DrawEdge(hdc, &widgetRect, EDGE_SUNKEN, BF_RECT | BF_ADJUST);
-
-      // Fill in window color background
-      ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_WINDOW + 1));
-
-      break;
-    }
     // Draw 3D face background controls
     case StyleAppearance::ProgressBar:
       // Draw 3D border
@@ -1903,6 +1884,7 @@ uint32_t nsNativeThemeWin::GetWidgetNativeDrawingFlags(
   switch (aAppearance) {
     case StyleAppearance::Button:
     case StyleAppearance::NumberInput:
+    case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
     case StyleAppearance::Textarea:
     case StyleAppearance::Menulist:
diff --git a/widget/windows/nsUXThemeData.cpp b/widget/windows/nsUXThemeData.cpp
index ce8b0f3479..88546b01c6 100644
--- a/widget/windows/nsUXThemeData.cpp
+++ b/widget/windows/nsUXThemeData.cpp
@@ -72,8 +72,6 @@ const wchar_t* nsUXThemeData::GetClassName(nsUXThemeClass cls) {
       return L"Trackbar";
     case eUXCombobox:
       return L"Combobox";
-    case eUXHeader:
-      return L"Header";
     case eUXListview:
       return L"Listview";
     case eUXMenu:
diff --git a/widget/windows/nsUXThemeData.h b/widget/windows/nsUXThemeData.h
index 24fe07d128..b59c2aae04 100644
--- a/widget/windows/nsUXThemeData.h
+++ b/widget/windows/nsUXThemeData.h
@@ -24,7 +24,6 @@ enum nsUXThemeClass {
   eUXTab,
   eUXTrackbar,
   eUXCombobox,
-  eUXHeader,
   eUXListview,
   eUXMenu,
   eUXNumClasses
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 22d20d099e..ac393e8b09 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -166,7 +166,6 @@
 #include "mozilla/StaticPrefs_ui.h"
 #include "mozilla/StaticPrefs_widget.h"
 #include "nsNativeAppSupportWin.h"
-#include "mozilla/browser/NimbusFeatures.h"
 
 #include "nsIGfxInfo.h"
 #include "nsUXThemeConstants.h"
@@ -188,7 +187,6 @@
 #  include "mozilla/a11y/DocAccessible.h"
 #  include "mozilla/a11y/LazyInstantiator.h"
 #  include "mozilla/a11y/Platform.h"
-#  include "mozilla/StaticPrefs_accessibility.h"
 #  if !defined(WINABLEAPI)
 #    include <winable.h>
 #  endif  // !defined(WINABLEAPI)
@@ -348,6 +346,12 @@ static SystemTimeConverter<DWORD>& TimeConverter() {
   return timeConverterSingleton;
 }
 
+static const wchar_t* GetMainWindowClass();
+static const wchar_t* ChooseWindowClass(mozilla::widget::WindowType);
+// This method registers the given window class, and returns the class name.
+static void RegisterWindowClass(const wchar_t* aClassName, UINT aExtraStyle,
+                                LPWSTR aIconID);
+
 // Global event hook for window cloaking. Never deregistered.
 //  - `Nothing` if not yet set.
 //  - `Some(nullptr)` if no attempt should be made to set it.
@@ -990,13 +994,11 @@ nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
   }
 
   if (aInitData->mIsPrivate) {
-    if (NimbusFeatures::GetBool("majorRelease2022"_ns,
-                                "feltPrivacyWindowSeparation"_ns, true) &&
-        // Although permanent Private Browsing mode is indeed Private Browsing,
-        // we choose to make it look like regular Firefox in terms of the icon
-        // it uses (which also means we shouldn't use the Private Browsing
-        // AUMID).
-        !StaticPrefs::browser_privatebrowsing_autostart()) {
+    // Although permanent Private Browsing mode is indeed Private Browsing,
+    // we choose to make it look like regular Firefox in terms of the icon
+    // it uses (which also means we shouldn't use the Private Browsing
+    // AUMID).
+    if (!StaticPrefs::browser_privatebrowsing_autostart()) {
       RefPtr<IPropertyStore> pPropStore;
       if (!FAILED(SHGetPropertyStoreForWindow(mWnd, IID_IPropertyStore,
                                               getter_AddRefs(pPropStore)))) {
@@ -1189,40 +1191,28 @@ void nsWindow::Destroy() {
  *
  **************************************************************/
 
-/* static */
-const wchar_t* nsWindow::RegisterWindowClass(const wchar_t* aClassName,
-                                             UINT aExtraStyle, LPWSTR aIconID) {
-  WNDCLASSW wc;
+static void RegisterWindowClass(const wchar_t* aClassName, UINT aExtraStyle,
+                                LPWSTR aIconID) {
+  WNDCLASSW wc = {};
   if (::GetClassInfoW(nsToolkit::mDllInstance, aClassName, &wc)) {
     // already registered
-    return aClassName;
+    return;
   }
 
   wc.style = CS_DBLCLKS | aExtraStyle;
   wc.lpfnWndProc = WinUtils::NonClientDpiScalingDefWindowProcW;
-  wc.cbClsExtra = 0;
-  wc.cbWndExtra = 0;
   wc.hInstance = nsToolkit::mDllInstance;
   wc.hIcon =
       aIconID ? ::LoadIconW(::GetModuleHandleW(nullptr), aIconID) : nullptr;
-  wc.hCursor = nullptr;
-  wc.hbrBackground = nullptr;
-  wc.lpszMenuName = nullptr;
   wc.lpszClassName = aClassName;
 
-  if (!::RegisterClassW(&wc)) {
-    // For older versions of Win32 (i.e., not XP), the registration may
-    // fail with aExtraStyle, so we have to re-register without it.
-    wc.style = CS_DBLCLKS;
-    ::RegisterClassW(&wc);
-  }
-  return aClassName;
+  // Failures are ignored as they are handled when ::CreateWindow fails
+  ::RegisterClassW(&wc);
 }
 
 static LPWSTR const gStockApplicationIcon = MAKEINTRESOURCEW(32512);
 
-/* static */
-const wchar_t* nsWindow::ChooseWindowClass(WindowType aWindowType) {
+static const wchar_t* ChooseWindowClass(WindowType aWindowType) {
   const wchar_t* className = [aWindowType] {
     switch (aWindowType) {
       case WindowType::Invisible:
@@ -1235,7 +1225,8 @@ const wchar_t* nsWindow::ChooseWindowClass(WindowType aWindowType) {
         return GetMainWindowClass();
     }
   }();
-  return RegisterWindowClass(className, 0, gStockApplicationIcon);
+  RegisterWindowClass(className, 0, gStockApplicationIcon);
+  return className;
 }
 
 /**************************************************************
@@ -1246,24 +1237,62 @@ const wchar_t* nsWindow::ChooseWindowClass(WindowType aWindowType) {
  *
  **************************************************************/
 
+const DWORD kTitlebarItemsWindowStyles =
+    WS_SYSMENU | WS_MINIMIZEBOX | WS_MAXIMIZEBOX;
+const DWORD kAllBorderStyles =
+    kTitlebarItemsWindowStyles | WS_THICKFRAME | WS_DLGFRAME;
+
+static DWORD WindowStylesRemovedForBorderStyle(BorderStyle aStyle) {
+  if (aStyle == BorderStyle::Default || aStyle == BorderStyle::All) {
+    return 0;
+  }
+  if (aStyle == BorderStyle::None) {
+    return kAllBorderStyles;
+  }
+  DWORD toRemove = 0;
+  if (!(aStyle & BorderStyle::Border)) {
+    toRemove |= WS_BORDER;
+  }
+  if (!(aStyle & BorderStyle::Title)) {
+    toRemove |= WS_DLGFRAME;
+  }
+  if (!(aStyle & (BorderStyle::Menu | BorderStyle::Close))) {
+    // Looks like getting rid of the system menu also does away with the close
+    // box. So, we only get rid of the system menu and the close box if you
+    // want neither. How does the Windows "Dialog" window class get just
+    // closebox and no sysmenu? Who knows.
+    toRemove |= WS_SYSMENU;
+  }
+  if (!(aStyle & BorderStyle::ResizeH)) {
+    toRemove |= WS_THICKFRAME;
+  }
+  if (!(aStyle & BorderStyle::Minimize)) {
+    toRemove |= WS_MINIMIZEBOX;
+  }
+  if (!(aStyle & BorderStyle::Maximize)) {
+    toRemove |= WS_MAXIMIZEBOX;
+  }
+  return toRemove;
+}
+
 // Return nsWindow styles
 DWORD nsWindow::WindowStyle() {
   DWORD style;
-
   switch (mWindowType) {
     case WindowType::Child:
       style = WS_OVERLAPPED;
       break;
 
     case WindowType::Dialog:
-      style = WS_OVERLAPPED | WS_BORDER | WS_DLGFRAME | WS_SYSMENU | DS_3DLOOK |
+      style = WS_OVERLAPPED | WS_BORDER | WS_DLGFRAME | WS_SYSMENU |
               DS_MODALFRAME | WS_CLIPCHILDREN;
-      if (mBorderStyle != BorderStyle::Default)
+      if (mBorderStyle != BorderStyle::Default) {
         style |= WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX;
+      }
       break;
 
     case WindowType::Popup:
-      style = WS_POPUP | WS_OVERLAPPED;
+      style = WS_OVERLAPPED | WS_POPUP;
       break;
 
     default:
@@ -1272,48 +1301,12 @@ DWORD nsWindow::WindowStyle() {
 
     case WindowType::TopLevel:
     case WindowType::Invisible:
-      style = WS_OVERLAPPED | WS_BORDER | WS_DLGFRAME | WS_SYSMENU |
-              WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_CLIPCHILDREN;
+      style = WS_OVERLAPPED | WS_CLIPCHILDREN | WS_DLGFRAME | WS_BORDER |
+              WS_THICKFRAME | kTitlebarItemsWindowStyles;
       break;
   }
 
-  if (mBorderStyle != BorderStyle::Default &&
-      mBorderStyle != BorderStyle::All) {
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::Border))
-      style &= ~WS_BORDER;
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::Title)) {
-      style &= ~WS_DLGFRAME;
-    }
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::Close))
-      style &= ~0;
-    // XXX The close box can only be removed by changing the window class,
-    // as far as I know   --- roc+moz@cs.cmu.edu
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & (BorderStyle::Menu | BorderStyle::Close)))
-      style &= ~WS_SYSMENU;
-    // Looks like getting rid of the system menu also does away with the
-    // close box. So, we only get rid of the system menu if you want neither it
-    // nor the close box. How does the Windows "Dialog" window class get just
-    // closebox and no sysmenu? Who knows.
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::ResizeH))
-      style &= ~WS_THICKFRAME;
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::Minimize))
-      style &= ~WS_MINIMIZEBOX;
-
-    if (mBorderStyle == BorderStyle::None ||
-        !(mBorderStyle & BorderStyle::Maximize))
-      style &= ~WS_MAXIMIZEBOX;
-  }
+  style &= ~WindowStylesRemovedForBorderStyle(mBorderStyle);
 
   if (mIsChildWindow) {
     style |= WS_CLIPCHILDREN;
@@ -2471,46 +2464,6 @@ void nsWindow::ResetLayout() {
   Invalidate();
 }
 
-// Internally track the caption status via a window property. Required
-// due to our internal handling of WM_NCACTIVATE when custom client
-// margins are set.
-static const wchar_t kManageWindowInfoProperty[] = L"ManageWindowInfoProperty";
-typedef BOOL(WINAPI* GetWindowInfoPtr)(HWND hwnd, PWINDOWINFO pwi);
-static WindowsDllInterceptor::FuncHookType<GetWindowInfoPtr>
-    sGetWindowInfoPtrStub;
-
-BOOL WINAPI GetWindowInfoHook(HWND hWnd, PWINDOWINFO pwi) {
-  if (!sGetWindowInfoPtrStub) {
-    NS_ASSERTION(FALSE, "Something is horribly wrong in GetWindowInfoHook!");
-    return FALSE;
-  }
-  int windowStatus =
-      reinterpret_cast<LONG_PTR>(GetPropW(hWnd, kManageWindowInfoProperty));
-  // No property set, return the default data.
-  if (!windowStatus) return sGetWindowInfoPtrStub(hWnd, pwi);
-  // Call GetWindowInfo and update dwWindowStatus with our
-  // internally tracked value.
-  BOOL result = sGetWindowInfoPtrStub(hWnd, pwi);
-  if (result && pwi)
-    pwi->dwWindowStatus = (windowStatus == 1 ? 0 : WS_ACTIVECAPTION);
-  return result;
-}
-
-void nsWindow::UpdateGetWindowInfoCaptionStatus(bool aActiveCaption) {
-  if (!mWnd) return;
-
-  sUser32Intercept.Init("user32.dll");
-  sGetWindowInfoPtrStub.Set(sUser32Intercept, "GetWindowInfo",
-                            &GetWindowInfoHook);
-  if (!sGetWindowInfoPtrStub) {
-    return;
-  }
-
-  // Update our internally tracked caption status
-  SetPropW(mWnd, kManageWindowInfoProperty,
-           reinterpret_cast<HANDLE>(static_cast<INT_PTR>(aActiveCaption) + 1));
-}
-
 #define DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1 19
 #define DWMWA_USE_IMMERSIVE_DARK_MODE 20
 
@@ -2703,6 +2656,8 @@ bool nsWindow::UpdateNonClientMargins(bool aReflowWindow) {
     mNonClientOffset = NormalWindowNonClientOffset();
   }
 
+  UpdateOpaqueRegionInternal();
+
   if (aReflowWindow) {
     // Force a reflow of content based on the new client
     // dimensions.
@@ -2713,8 +2668,9 @@ bool nsWindow::UpdateNonClientMargins(bool aReflowWindow) {
 }
 
 nsresult nsWindow::SetNonClientMargins(const LayoutDeviceIntMargin& margins) {
-  if (!mIsTopWidgetWindow || mBorderStyle == BorderStyle::None)
+  if (!mIsTopWidgetWindow || mBorderStyle == BorderStyle::None) {
     return NS_ERROR_INVALID_ARG;
+  }
 
   if (mHideChrome) {
     mFutureMarginsOnceChromeShows = margins;
@@ -2731,19 +2687,13 @@ nsresult nsWindow::SetNonClientMargins(const LayoutDeviceIntMargin& margins) {
     // Force a reflow of content based on the new client
     // dimensions.
     ResetLayout();
-
-    int windowStatus =
-        reinterpret_cast<LONG_PTR>(GetPropW(mWnd, kManageWindowInfoProperty));
-    if (windowStatus) {
-      ::SendMessageW(mWnd, WM_NCACTIVATE, 1 != windowStatus, 0);
-    }
-
     return NS_OK;
   }
 
   if (margins.top < -1 || margins.bottom < -1 || margins.left < -1 ||
-      margins.right < -1)
+      margins.right < -1) {
     return NS_ERROR_INVALID_ARG;
+  }
 
   mNonClientMargins = margins;
   mCustomNonClient = true;
@@ -3999,10 +3949,8 @@ uint32_t nsWindow::GetMaxTouchPoints() const {
   return WinUtils::GetMaxTouchPoints();
 }
 
-void nsWindow::SetWindowClass(const nsAString& xulWinType,
-                              const nsAString& xulWinClass,
-                              const nsAString& xulWinName) {
-  mIsEarlyBlankWindow = xulWinType.EqualsLiteral("navigator:blank");
+void nsWindow::SetIsEarlyBlankWindow(bool aIsEarlyBlankWindow) {
+  mIsEarlyBlankWindow = aIsEarlyBlankWindow;
 }
 
 /**************************************************************
@@ -5194,8 +5142,6 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
        * WM_NCACTIVATE paints nc areas. Avoid this and re-route painting
        * through WM_NCPAINT via InvalidateNonClientRegion.
        */
-      UpdateGetWindowInfoCaptionStatus(FALSE != wParam);
-
       if (!mCustomNonClient) {
         break;
       }
@@ -5684,9 +5630,6 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
         if (WinUtils::LogToPhysFactor(mWnd) != mDefaultScale) {
           ChangedDPI();
           ResetLayout();
-          if (mWidgetListener) {
-            mWidgetListener->UIResolutionChanged();
-          }
         }
       }
       break;
@@ -5724,9 +5667,6 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
 
     case WM_DISPLAYCHANGE: {
       ScreenHelperWin::RefreshScreens();
-      if (mWidgetListener) {
-        mWidgetListener->UIResolutionChanged();
-      }
       break;
     }
 
@@ -5925,19 +5865,12 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
           a11y::LazyInstantiator::EnableBlindAggregation(mWnd);
           result = true;
         }
-      } else if (objId == UiaRootObjectId &&
-                 StaticPrefs::accessibility_uia_enable()) {
-        if (a11y::LocalAccessible* acc = GetAccessible()) {
-          RefPtr<IAccessible> ia;
-          acc->GetNativeInterface(getter_AddRefs(ia));
-          MOZ_ASSERT(ia);
-          RefPtr<IRawElementProviderSimple> uia;
-          ia->QueryInterface(IID_IRawElementProviderSimple,
-                             getter_AddRefs(uia));
-          if (uia) {
-            *aRetValue = UiaReturnRawElementProvider(mWnd, wParam, lParam, uia);
-            result = true;
-          }
+      } else if (objId == UiaRootObjectId) {
+        if (RefPtr<IRawElementProviderSimple> root =
+                a11y::LazyInstantiator::GetRootUia(mWnd)) {
+          *aRetValue = UiaReturnRawElementProvider(mWnd, wParam, lParam, root);
+          a11y::LazyInstantiator::EnableBlindAggregation(mWnd);
+          result = true;
         }
       }
     } break;
@@ -7420,7 +7353,9 @@ a11y::LocalAccessible* nsWindow::GetAccessible() {
  **************************************************************/
 
 void nsWindow::SetWindowTranslucencyInner(TransparencyMode aMode) {
-  if (aMode == mTransparencyMode) return;
+  if (aMode == mTransparencyMode) {
+    return;
+  }
 
   // stop on dialogs and popups!
   HWND hWnd = WinUtils::GetTopLevelHWND(mWnd, true);
@@ -7458,10 +7393,11 @@ void nsWindow::SetWindowTranslucencyInner(TransparencyMode aMode) {
     }
   }
 
-  if (aMode == TransparencyMode::Transparent)
+  if (aMode == TransparencyMode::Transparent) {
     exStyle |= WS_EX_LAYERED;
-  else
+  } else {
     exStyle &= ~WS_EX_LAYERED;
+  }
 
   VERIFY_WINDOW_STYLE(style);
   ::SetWindowLongPtrW(hWnd, GWL_STYLE, style);
@@ -7469,11 +7405,47 @@ void nsWindow::SetWindowTranslucencyInner(TransparencyMode aMode) {
 
   mTransparencyMode = aMode;
 
+  UpdateOpaqueRegionInternal();
+
   if (mCompositorWidgetDelegate) {
     mCompositorWidgetDelegate->UpdateTransparency(aMode);
   }
 }
 
+void nsWindow::UpdateOpaqueRegion(const LayoutDeviceIntRegion& aRegion) {
+  if (aRegion == mOpaqueRegion) {
+    return;
+  }
+  mOpaqueRegion = aRegion;
+  UpdateOpaqueRegionInternal();
+}
+
+void nsWindow::UpdateOpaqueRegionInternal() {
+  MARGINS margins{0};
+  if (mTransparencyMode == TransparencyMode::Transparent) {
+    // If there is no opaque region, set margins to support a full sheet of
+    // glass. Comments in MSDN indicate all values must be set to -1 to get a
+    // full sheet of glass.
+    margins = {-1, -1, -1, -1};
+    if (!mOpaqueRegion.IsEmpty()) {
+      LayoutDeviceIntRect clientBounds = GetClientBounds();
+      // Find the largest rectangle and use that to calculate the inset.
+      LayoutDeviceIntRect largest = mOpaqueRegion.GetLargestRectangle();
+      margins.cxLeftWidth = largest.X();
+      margins.cxRightWidth = clientBounds.Width() - largest.XMost();
+      margins.cyBottomHeight = clientBounds.Height() - largest.YMost();
+      margins.cyTopHeight = largest.Y();
+
+      auto ncmargin = NonClientSizeMargin();
+      margins.cxLeftWidth += ncmargin.left;
+      margins.cyTopHeight += ncmargin.top;
+      margins.cxRightWidth += ncmargin.right;
+      margins.cyBottomHeight += ncmargin.bottom;
+    }
+  }
+  DwmExtendFrameIntoClientArea(mWnd, &margins);
+}
+
 /**************************************************************
  **************************************************************
  **
@@ -8200,7 +8172,7 @@ bool nsWindow::CanTakeFocus() {
   return false;
 }
 
-/* static */ const wchar_t* nsWindow::GetMainWindowClass() {
+static const wchar_t* GetMainWindowClass() {
   static const wchar_t* sMainWindowClass = nullptr;
   if (!sMainWindowClass) {
     nsAutoString className;
diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
index a2b2a701bd..9c4b4417f8 100644
--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -261,8 +261,7 @@ class nsWindow final : public nsBaseWidget {
       const LayoutDeviceIntRegion& aRegion) override;
 
   uint32_t GetMaxTouchPoints() const override;
-  void SetWindowClass(const nsAString& xulWinType, const nsAString& xulWinClass,
-                      const nsAString& xulWinName) override;
+  void SetIsEarlyBlankWindow(bool) override;
 
   /**
    * Event helpers
@@ -518,10 +517,8 @@ class nsWindow final : public nsBaseWidget {
   bool CanTakeFocus();
   bool UpdateNonClientMargins(bool aReflowWindow = true);
   void UpdateDarkModeToolbar();
-  void UpdateGetWindowInfoCaptionStatus(bool aActiveCaption);
   void ResetLayout();
   void InvalidateNonClientRegion();
-  static const wchar_t* GetMainWindowClass();
   HWND GetOwnerWnd() const { return ::GetWindow(mWnd, GW_OWNER); }
   bool IsOwnerForegroundWindow() const {
     HWND owner = GetOwnerWnd();
@@ -592,11 +589,6 @@ class nsWindow final : public nsBaseWidget {
   DWORD WindowStyle();
   DWORD WindowExStyle();
 
-  static const wchar_t* ChooseWindowClass(WindowType);
-  // This method registers the given window class, and returns the class name.
-  static const wchar_t* RegisterWindowClass(const wchar_t* aClassName,
-                                            UINT aExtraStyle, LPWSTR aIconID);
-
   /**
    * Popup hooks
    */
@@ -620,6 +612,9 @@ class nsWindow final : public nsBaseWidget {
   bool IsSimulatedClientArea(int32_t clientX, int32_t clientY);
   bool IsWindowButton(int32_t hitTestResult);
 
+  void UpdateOpaqueRegion(const LayoutDeviceIntRegion&) override;
+  void UpdateOpaqueRegionInternal();
+
   bool DispatchTouchEventFromWMPointer(UINT msg, LPARAM aLParam,
                                        const WinPointerInfo& aPointerInfo,
                                        mozilla::MouseButton aButton);
@@ -808,6 +803,8 @@ class nsWindow final : public nsBaseWidget {
 
   // Draggable titlebar region maintained by UpdateWindowDraggingRegion
   LayoutDeviceIntRegion mDraggableRegion;
+  // Opaque region maintained by UpdateOpaqueRegion
+  LayoutDeviceIntRegion mOpaqueRegion;
 
   // Graphics
   LayoutDeviceIntRect mLastPaintBounds;
@@ -816,7 +813,6 @@ class nsWindow final : public nsBaseWidget {
 
   // Transparency
   TransparencyMode mTransparencyMode = TransparencyMode::Opaque;
-  nsIntRegion mPossiblyTransparentRegion;
 
   // Win7 Gesture processing and management
   nsWinGesture mGesture;
diff --git a/widget/windows/tests/gtest/TestJumpListBuilder.cpp b/widget/windows/tests/gtest/TestJumpListBuilder.cpp
index 5494c42d37..531e326465 100644
--- a/widget/windows/tests/gtest/TestJumpListBuilder.cpp
+++ b/widget/windows/tests/gtest/TestJumpListBuilder.cpp
@@ -275,14 +275,14 @@ class TestingJumpListBackend : public JumpListBackend {
  * @param {nsTArray<WindowsJumpListShortcutDescription>&} aArray
  *   The outparam for the array of generated
  * WindowsJumpListShortcutDescriptions.
- * @param {nsTArray<JS::Value>&} aJSValArray
+ * @param {JS::Handle<JSObject*>} aJSArrayObj
  *   The outparam for the array of JS::Value's representing the generated
  *   WindowsJumpListShortcutDescriptions.
  */
 void GenerateWindowsJumpListShortcutDescriptions(
     JSContext* aCx, uint32_t howMany, bool longDescription,
     nsTArray<WindowsJumpListShortcutDescription>& aArray,
-    nsTArray<JS::Value>& aJSValArray) {
+    JS::Handle<JSObject*> aJSArrayObj) {
   for (uint32_t i = 0; i < howMany; ++i) {
     WindowsJumpListShortcutDescription desc;
     nsAutoString title(u"Test Task #");
@@ -321,7 +321,8 @@ void GenerateWindowsJumpListShortcutDescriptions(
     aArray.AppendElement(desc);
     JS::Rooted<JS::Value> descJSValue(aCx);
     ASSERT_TRUE(ToJSValue(aCx, desc, &descJSValue));
-    aJSValArray.AppendElement(std::move(descJSValue));
+
+    MOZ_ALWAYS_TRUE(JS_SetElement(aCx, aJSArrayObj, i, descJSValue));
   }
 }
 
@@ -393,15 +394,15 @@ TEST(JumpListBuilder, CheckForRemovals)
   EXPECT_CALL(*testBackend, BeginList)
       .WillOnce([](UINT* pcMinSlots, REFIID riid, void** ppv) {
         RefPtr<IObjectCollection> collection;
-        DebugOnly<HRESULT> hr = CoCreateInstance(
+        HRESULT hr = CoCreateInstance(
             CLSID_EnumerableObjectCollection, nullptr, CLSCTX_INPROC_SERVER,
             IID_IObjectCollection, getter_AddRefs(collection));
-        MOZ_ASSERT(SUCCEEDED(hr));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
 
         RefPtr<IShellLinkW> link;
         hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
                               IID_IShellLinkW, getter_AddRefs(link));
-        MOZ_ASSERT(SUCCEEDED(hr));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
 
         nsAutoString firstLinkHref(u"https://example.com"_ns);
         link->SetArguments(firstLinkHref.get());
@@ -421,7 +422,7 @@ TEST(JumpListBuilder, CheckForRemovals)
         RefPtr<IObjectArray> pArray;
         hr = collection->QueryInterface(IID_IObjectArray,
                                         getter_AddRefs(pArray));
-        MOZ_ASSERT(SUCCEEDED(hr));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
 
         *ppv = static_cast<IObjectArray*>(pArray);
         (static_cast<IUnknown*>(*ppv))->AddRef();
@@ -478,6 +479,115 @@ TEST(JumpListBuilder, CheckForRemovals)
 }
 
 /**
+ * Tests calling CheckForRemovals and receiving a jump list entry with a very
+ * long URL doesn't result in JumpListBuilder truncating the URL before handing
+ * it back to the caller. Expects the following calls in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AbortList
+ */
+TEST(JumpListBuilder, CheckForRemovalsLongURL)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(2);
+
+  constexpr static const nsLiteralString veryLongHref(
+      u"https://example.verylongurl.test/first/second/third/fourth/fifth/"
+      "sixth/seventh/eighth/ninth/tenth/eleventh/twelfth/thirteenth/"
+      "fourteenth/fifteenth-path-item/some/more/junk/after/that/more/more/"
+      "more/more/more/more/more/more/more/more/more/more/more/more/more/more/"
+      "more/more/more/more/more/more/more/more/more/more/more"_ns);
+  // This test ensures that URLs longer than MAX_PATH do not get truncated by
+  // JumpListBuilder or one of its utilities, so we must ensure that the static
+  // URL we just defined is actually longer than MAX_PATH.
+  static_assert(veryLongHref.Length() > MAX_PATH);
+
+  // Let's prepare BeginList to return a one entry collection of IShellLinks.
+  // The IShellLink will have the URL be very long - over MAX_PATH characters.
+  EXPECT_CALL(*testBackend, BeginList)
+      .WillOnce([](UINT* pcMinSlots, REFIID riid, void** ppv) {
+        RefPtr<IObjectCollection> collection;
+        HRESULT hr = CoCreateInstance(
+            CLSID_EnumerableObjectCollection, nullptr, CLSCTX_INPROC_SERVER,
+            IID_IObjectCollection, getter_AddRefs(collection));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
+
+        RefPtr<IShellLinkW> link;
+        hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                              IID_IShellLinkW, getter_AddRefs(link));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
+
+        link->SetArguments(veryLongHref.get());
+
+        nsAutoString appPath(u"C:\\Tmp\\firefox.exe"_ns);
+        link->SetIconLocation(appPath.get(), 0);
+
+        collection->AddObject(link);
+
+        RefPtr<IObjectArray> pArray;
+        hr = collection->QueryInterface(IID_IObjectArray,
+                                        getter_AddRefs(pArray));
+        MOZ_RELEASE_ASSERT(SUCCEEDED(hr));
+
+        *ppv = static_cast<IObjectArray*>(pArray);
+        (static_cast<IUnknown*>(*ppv))->AddRef();
+
+        // This is the default value to return, according to
+        // https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-icustomdestinationlist-beginlist
+        *pcMinSlots = 10;
+
+        return S_OK;
+      });
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+  nsresult rv = builder->CheckForRemovals(cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolvedWithResult(&result);
+
+  ASSERT_TRUE(result.isObject());
+  JS::Rooted<JSObject*> obj(cx, result.toObjectOrNull());
+
+  bool isArray;
+  ASSERT_TRUE(JS::IsArrayObject(cx, obj, &isArray));
+  ASSERT_TRUE(isArray);
+
+  // We should expect to see 1 URL string returned in the array.
+  uint32_t length = 0;
+  ASSERT_TRUE(JS::GetArrayLength(cx, obj, &length));
+  ASSERT_EQ(length, 1U);
+
+  // The URL should match veryLongHref
+  JS::Rooted<JS::Value> returnedURLValue(cx);
+  ASSERT_TRUE(JS_GetElement(cx, obj, 0, &returnedURLValue));
+  JS::Rooted<JSString*> returnedURLValueJSString(cx,
+                                                 returnedURLValue.toString());
+  nsAutoJSString returnedURLValueAutoString;
+  ASSERT_TRUE(returnedURLValueAutoString.init(cx, returnedURLValueJSString));
+
+  ASSERT_TRUE(returnedURLValueAutoString.Equals(veryLongHref));
+}
+
+/**
  * Tests calling PopulateJumpList with empty arguments, which should call the
  * following methods on the backend, in order:
  *
@@ -506,9 +616,13 @@ TEST(JumpListBuilder, PopulateJumpListEmpty)
   JSContext* cx = jsapi.cx();
   RefPtr<Promise> promise;
 
-  nsTArray<JS::Value> taskDescJSVals;
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx, JS::ObjectValue(*taskDescsObj));
+
   nsAutoString customTitle(u"");
-  nsTArray<JS::Value> customDescJSVals;
+
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
 
   EXPECT_CALL(*testBackend, AbortList()).Times(1);
   EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
@@ -516,7 +630,7 @@ TEST(JumpListBuilder, PopulateJumpListEmpty)
   EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
 
   nsresult rv =
-      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
                                 cx, getter_AddRefs(promise));
   ASSERT_TRUE(NS_SUCCEEDED(rv));
   ASSERT_TRUE(promise);
@@ -558,13 +672,15 @@ TEST(JumpListBuilder, PopulateJumpListOnlyTasks)
   JSContext* cx = jsapi.cx();
   RefPtr<Promise> promise;
 
-  nsTArray<JS::Value> taskDescJSVals;
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx, JS::ObjectValue(*taskDescsObj));
   nsTArray<WindowsJumpListShortcutDescription> taskDescs;
   GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, taskDescs,
-                                              taskDescJSVals);
+                                              taskDescsObj);
 
   nsAutoString customTitle(u"");
-  nsTArray<JS::Value> customDescJSVals;
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
 
   EXPECT_CALL(*testBackend, AbortList()).Times(1);
   EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
@@ -575,7 +691,7 @@ TEST(JumpListBuilder, PopulateJumpListOnlyTasks)
   EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
 
   nsresult rv =
-      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
                                 cx, getter_AddRefs(promise));
   ASSERT_TRUE(NS_SUCCEEDED(rv));
   ASSERT_TRUE(promise);
@@ -617,13 +733,17 @@ TEST(JumpListBuilder, PopulateJumpListOnlyCustomItems)
   JSContext* cx = jsapi.cx();
   RefPtr<Promise> promise;
 
-  nsTArray<WindowsJumpListShortcutDescription> descs;
-  nsTArray<JS::Value> customDescJSVals;
-  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, descs,
-                                              customDescJSVals);
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx);
+  taskDescsJSVal.setObject(*taskDescsObj);
 
   nsAutoString customTitle(u"My custom title");
-  nsTArray<JS::Value> taskDescJSVals;
+
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
+  nsTArray<WindowsJumpListShortcutDescription> descs;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, descs,
+                                              customDescsObj);
 
   EXPECT_CALL(*testBackend, AbortList()).Times(1);
   EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
@@ -636,7 +756,7 @@ TEST(JumpListBuilder, PopulateJumpListOnlyCustomItems)
   EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
 
   nsresult rv =
-      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
                                 cx, getter_AddRefs(promise));
   ASSERT_TRUE(NS_SUCCEEDED(rv));
   ASSERT_TRUE(promise);
@@ -679,30 +799,102 @@ TEST(JumpListBuilder, PopulateJumpList)
   JSContext* cx = jsapi.cx();
   RefPtr<Promise> promise;
 
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx, JS::ObjectValue(*taskDescsObj));
   nsTArray<WindowsJumpListShortcutDescription> taskDescs;
-  nsTArray<JS::Value> taskDescJSVals;
   GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, taskDescs,
-                                              taskDescJSVals);
+                                              taskDescsObj);
+
+  nsAutoString customTitle(u"My custom title");
 
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
   nsTArray<WindowsJumpListShortcutDescription> customDescs;
-  nsTArray<JS::Value> customDescJSVals;
   GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, customDescs,
-                                              customDescJSVals);
+                                              customDescsObj);
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
+
+  EXPECT_CALL(*testBackend, AppendCategory(LPCWSTREq(customTitle.get()),
+                                           ShellLinksEq(&customDescs)))
+      .Times(1);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Tests calling PopulateJumpList with tasks and custom items, but makes it so
+ * that AppendCategory returns E_ACCESSDENIED, which can occur if Windows is
+ * configured to not show recently opened items. The PopulateJumpList Promise
+ * should still resolve.
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AddUserTasks
+ * - AppendCategory
+ * - CommitList
+ *
+ * This should result in a jump list with just built-in tasks.
+ */
+TEST(JumpListBuilder, PopulateJumpListNoOpenedItems)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx, JS::ObjectValue(*taskDescsObj));
+  nsTArray<WindowsJumpListShortcutDescription> taskDescs;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, taskDescs,
+                                              taskDescsObj);
 
   nsAutoString customTitle(u"My custom title");
 
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
+  nsTArray<WindowsJumpListShortcutDescription> customDescs;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, customDescs,
+                                              customDescsObj);
+
   EXPECT_CALL(*testBackend, AbortList()).Times(1);
   EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
   EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
 
   EXPECT_CALL(*testBackend, AppendCategory(LPCWSTREq(customTitle.get()),
                                            ShellLinksEq(&customDescs)))
-      .Times(1);
+      .WillOnce([] { return E_ACCESSDENIED; });
+
   EXPECT_CALL(*testBackend, CommitList()).Times(1);
   EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
 
   nsresult rv =
-      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
                                 cx, getter_AddRefs(promise));
   ASSERT_TRUE(NS_SUCCEEDED(rv));
   ASSERT_TRUE(promise);
@@ -780,15 +972,20 @@ TEST(JumpListBuilder, TruncateDescription)
   JSContext* cx = jsapi.cx();
   RefPtr<Promise> promise;
 
+  JS::Rooted<JSObject*> taskDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> taskDescsJSVal(cx, JS::ObjectValue(*taskDescsObj));
   nsTArray<WindowsJumpListShortcutDescription> taskDescs;
-  nsTArray<JS::Value> taskDescJSVals;
   GenerateWindowsJumpListShortcutDescriptions(cx, 2, true, taskDescs,
-                                              taskDescJSVals);
+                                              taskDescsObj);
 
+  nsAutoString customTitle(u"My custom title");
+
+  JS::Rooted<JSObject*> customDescsObj(cx, JS::NewArrayObject(cx, 0));
+  JS::Rooted<JS::Value> customDescsJSVal(cx, JS::ObjectValue(*customDescsObj));
   nsTArray<WindowsJumpListShortcutDescription> customDescs;
-  nsTArray<JS::Value> customDescJSVals;
   GenerateWindowsJumpListShortcutDescriptions(cx, 2, true, customDescs,
-                                              customDescJSVals);
+                                              customDescsObj);
+
   // We expect the long descriptions to be truncated to 260 characters, so
   // we'll truncate the descriptions here ourselves.
   for (auto& taskDesc : taskDescs) {
@@ -798,8 +995,6 @@ TEST(JumpListBuilder, TruncateDescription)
     customDesc.mDescription.SetLength(MAX_PATH - 1);
   }
 
-  nsAutoString customTitle(u"My custom title");
-
   EXPECT_CALL(*testBackend, AbortList()).Times(1);
   EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
   EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
@@ -811,7 +1006,7 @@ TEST(JumpListBuilder, TruncateDescription)
   EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
 
   nsresult rv =
-      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+      builder->PopulateJumpList(taskDescsJSVal, customTitle, customDescsJSVal,
                                 cx, getter_AddRefs(promise));
   ASSERT_TRUE(NS_SUCCEEDED(rv));
   ASSERT_TRUE(promise);
diff --git a/widget/windows/tests/gtest/TestWinDND.cpp b/widget/windows/tests/gtest/TestWinDND.cpp
index fb7849fd79..9a4b8c3db1 100644
--- a/widget/windows/tests/gtest/TestWinDND.cpp
+++ b/widget/windows/tests/gtest/TestWinDND.cpp
@@ -693,7 +693,7 @@ nsCOMPtr<nsIFile> GetTemporaryDirectory() {
 #define ENSURE(expr) NS_ENSURE_SUCCESS(expr, nullptr);
 
   ENSURE(NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(tmpdir)));
-  MOZ_ASSERT(tmpdir);
+  MOZ_RELEASE_ASSERT(tmpdir);
 
   ENSURE(tmpdir->AppendNative("TestWinDND"_ns));
   ENSURE(tmpdir->CreateUnique(nsIFile::DIRECTORY_TYPE, 0777));