Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

1 files changed, 1120 insertions, 0 deletions

diff --git a/widget/cocoa/nsAppShell.mm b/widget/cocoa/nsAppShell.mm
new file mode 100644
index 0000000000..9ba512ce49
--- /dev/null
+++ b/widget/cocoa/nsAppShell.mm
@@ -0,0 +1,1120 @@
+/* -*- tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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/. */
+
+/*
+ * Runs the main native Cocoa run loop, interrupting it as needed to process
+ * Gecko events.
+ */
+
+#import <Cocoa/Cocoa.h>
+
+#include <dlfcn.h>
+
+#include "mozilla/AvailableMemoryWatcher.h"
+#include "CustomCocoaEvents.h"
+#include "mozilla/WidgetTraceEvent.h"
+#include "nsAppShell.h"
+#include "gfxPlatform.h"
+#include "nsCOMPtr.h"
+#include "nsIFile.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsString.h"
+#include "nsIRollupListener.h"
+#include "nsIWidget.h"
+#include "nsMemoryPressure.h"
+#include "nsThreadUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsCocoaUtils.h"
+#include "nsCocoaFeatures.h"
+#include "nsChildView.h"
+#include "nsToolkit.h"
+#include "TextInputHandler.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "ScreenHelperCocoa.h"
+#include "mozilla/Hal.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ProfilerThreadSleep.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "HeadlessScreenHelper.h"
+#include "MOZMenuOpeningCoordinator.h"
+#include "pratom.h"
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+#  include "nsSandboxViolationSink.h"
+#endif
+
+#include <IOKit/pwr_mgt/IOPMLib.h>
+#include "nsIDOMWakeLockListener.h"
+#include "nsIPowerManagerService.h"
+
+#include "nsIObserverService.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#define WAKE_LOCK_LOG(...) MOZ_LOG(gMacWakeLockLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+static mozilla::LazyLogModule gMacWakeLockLog("MacWakeLock");
+
+// A wake lock listener that disables screen saver when requested by
+// Gecko. For example when we're playing video in a foreground tab we
+// don't want the screen saver to turn on.
+
+class MacWakeLockListener final : public nsIDOMMozWakeLockListener {
+ public:
+  NS_DECL_ISUPPORTS;
+
+ private:
+  ~MacWakeLockListener() {}
+
+  IOPMAssertionID mAssertionNoDisplaySleepID = kIOPMNullAssertionID;
+  IOPMAssertionID mAssertionNoIdleSleepID = kIOPMNullAssertionID;
+
+  NS_IMETHOD Callback(const nsAString& aTopic, const nsAString& aState) override {
+    if (!aTopic.EqualsASCII("screen") && !aTopic.EqualsASCII("audio-playing") &&
+        !aTopic.EqualsASCII("video-playing")) {
+      return NS_OK;
+    }
+
+    // we should still hold the lock for background audio.
+    if (aTopic.EqualsASCII("audio-playing") && aState.EqualsASCII("locked-background")) {
+      WAKE_LOCK_LOG("keep audio playing even in background");
+      return NS_OK;
+    }
+
+    bool shouldKeepDisplayOn = aTopic.EqualsASCII("screen") || aTopic.EqualsASCII("video-playing");
+    CFStringRef assertionType =
+        shouldKeepDisplayOn ? kIOPMAssertionTypeNoDisplaySleep : kIOPMAssertionTypeNoIdleSleep;
+    IOPMAssertionID& assertionId =
+        shouldKeepDisplayOn ? mAssertionNoDisplaySleepID : mAssertionNoIdleSleepID;
+    WAKE_LOCK_LOG("topic=%s, state=%s, shouldKeepDisplayOn=%d", NS_ConvertUTF16toUTF8(aTopic).get(),
+                  NS_ConvertUTF16toUTF8(aState).get(), shouldKeepDisplayOn);
+
+    // Note the wake lock code ensures that we're not sent duplicate
+    // "locked-foreground" notifications when multiple wake locks are held.
+    if (aState.EqualsASCII("locked-foreground")) {
+      if (assertionId != kIOPMNullAssertionID) {
+        WAKE_LOCK_LOG("already has a lock");
+        return NS_OK;
+      }
+      // Prevent screen saver.
+      CFStringRef cf_topic = ::CFStringCreateWithCharacters(
+          kCFAllocatorDefault, reinterpret_cast<const UniChar*>(aTopic.Data()), aTopic.Length());
+      IOReturn success = ::IOPMAssertionCreateWithName(assertionType, kIOPMAssertionLevelOn,
+                                                       cf_topic, &assertionId);
+      CFRelease(cf_topic);
+      if (success != kIOReturnSuccess) {
+        WAKE_LOCK_LOG("failed to disable screensaver");
+      }
+      WAKE_LOCK_LOG("create screensaver");
+    } else {
+      // Re-enable screen saver.
+      if (assertionId != kIOPMNullAssertionID) {
+        IOReturn result = ::IOPMAssertionRelease(assertionId);
+        if (result != kIOReturnSuccess) {
+          WAKE_LOCK_LOG("failed to release screensaver");
+        }
+        WAKE_LOCK_LOG("Release screensaver");
+        assertionId = kIOPMNullAssertionID;
+      }
+    }
+    return NS_OK;
+  }
+};  // MacWakeLockListener
+
+// defined in nsCocoaWindow.mm
+extern int32_t gXULModalLevel;
+
+static bool gAppShellMethodsSwizzled = false;
+
+void OnUncaughtException(NSException* aException) {
+  nsObjCExceptionLog(aException);
+  MOZ_CRASH("Uncaught Objective C exception from NSSetUncaughtExceptionHandler");
+}
+
+@implementation GeckoNSApplication
+
+// Load is called very early during startup, when the Objective C runtime loads this class.
++ (void)load {
+  NSSetUncaughtExceptionHandler(OnUncaughtException);
+}
+
+// This method is called from NSDefaultTopLevelErrorHandler, which is invoked when an Objective C
+// exception propagates up into the native event loop. It is possible that it is also called in
+// other cases.
+- (void)reportException:(NSException*)aException {
+  if (ShouldIgnoreObjCException(aException)) {
+    return;
+  }
+
+  nsObjCExceptionLog(aException);
+
+#ifdef NIGHTLY_BUILD
+  MOZ_CRASH("Uncaught Objective C exception from -[GeckoNSApplication reportException:]");
+#endif
+}
+
+- (void)sendEvent:(NSEvent*)anEvent {
+  mozilla::BackgroundHangMonitor().NotifyActivity();
+
+  if ([anEvent type] == NSEventTypeApplicationDefined && [anEvent subtype] == kEventSubtypeTrace) {
+    mozilla::SignalTracerThread();
+    return;
+  }
+  [super sendEvent:anEvent];
+}
+
+- (NSEvent*)nextEventMatchingMask:(NSEventMask)mask
+                        untilDate:(NSDate*)expiration
+                           inMode:(NSString*)mode
+                          dequeue:(BOOL)flag {
+  if (expiration) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+  NSEvent* nextEvent = [super nextEventMatchingMask:mask
+                                          untilDate:expiration
+                                             inMode:mode
+                                            dequeue:flag];
+  if (expiration) {
+    mozilla::BackgroundHangMonitor().NotifyActivity();
+  }
+  return nextEvent;
+}
+
+@end
+
+// AppShellDelegate
+//
+// Cocoa bridge class.  An object of this class is registered to receive
+// notifications.
+//
+@interface AppShellDelegate : NSObject {
+ @private
+  nsAppShell* mAppShell;
+}
+
+- (id)initWithAppShell:(nsAppShell*)aAppShell;
+- (void)applicationWillTerminate:(NSNotification*)aNotification;
+- (BOOL)shouldSaveApplicationState:(NSCoder*)coder;
+- (BOOL)shouldRestoreApplicationState:(NSCoder*)coder;
+@end
+
+// nsAppShell implementation
+
+NS_IMETHODIMP
+nsAppShell::ResumeNative(void) {
+  nsresult retval = nsBaseAppShell::ResumeNative();
+  if (NS_SUCCEEDED(retval) && (mSuspendNativeCount == 0) && mSkippedNativeCallback) {
+    mSkippedNativeCallback = false;
+    ScheduleNativeEventCallback();
+  }
+  return retval;
+}
+
+nsAppShell::nsAppShell()
+    : mAutoreleasePools(nullptr),
+      mDelegate(nullptr),
+      mCFRunLoop(NULL),
+      mCFRunLoopSource(NULL),
+      mRunningEventLoop(false),
+      mStarted(false),
+      mTerminated(false),
+      mSkippedNativeCallback(false),
+      mNativeEventCallbackDepth(0),
+      mNativeEventScheduledDepth(0) {
+  // A Cocoa event loop is running here if (and only if) we've been embedded
+  // by a Cocoa app.
+  mRunningCocoaEmbedded = [NSApp isRunning] ? true : false;
+}
+
+nsAppShell::~nsAppShell() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  hal::Shutdown();
+
+  if (mMemoryPressureSource) {
+    dispatch_release(mMemoryPressureSource);
+    mMemoryPressureSource = nullptr;
+  }
+
+  if (mCFRunLoop) {
+    if (mCFRunLoopSource) {
+      ::CFRunLoopRemoveSource(mCFRunLoop, mCFRunLoopSource, kCFRunLoopCommonModes);
+      ::CFRelease(mCFRunLoopSource);
+    }
+    if (mCFRunLoopObserver) {
+      ::CFRunLoopRemoveObserver(mCFRunLoop, mCFRunLoopObserver, kCFRunLoopCommonModes);
+      ::CFRelease(mCFRunLoopObserver);
+    }
+    ::CFRelease(mCFRunLoop);
+  }
+
+  if (mAutoreleasePools) {
+    NS_ASSERTION(::CFArrayGetCount(mAutoreleasePools) == 0,
+                 "nsAppShell destroyed without popping all autorelease pools");
+    ::CFRelease(mAutoreleasePools);
+  }
+
+  [mDelegate release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+NS_IMPL_ISUPPORTS(MacWakeLockListener, nsIDOMMozWakeLockListener)
+mozilla::StaticRefPtr<MacWakeLockListener> sWakeLockListener;
+
+static void AddScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sWakeLockListener = new MacWakeLockListener();
+    sPowerManagerService->AddWakeLockListener(sWakeLockListener);
+  } else {
+    NS_WARNING("Failed to retrieve PowerManagerService, wakelocks will be broken!");
+  }
+}
+
+static void RemoveScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sPowerManagerService->RemoveWakeLockListener(sWakeLockListener);
+    sPowerManagerService = nullptr;
+    sWakeLockListener = nullptr;
+  }
+}
+
+void RunLoopObserverCallback(CFRunLoopObserverRef aObserver, CFRunLoopActivity aActivity,
+                             void* aInfo) {
+  static_cast<nsAppShell*>(aInfo)->OnRunLoopActivityChanged(aActivity);
+}
+
+void nsAppShell::OnRunLoopActivityChanged(CFRunLoopActivity aActivity) {
+  if (aActivity == kCFRunLoopBeforeWaiting) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+
+  // When the event loop is in its waiting state, we would like the profiler to know that the thread
+  // is idle. The usual way to notify the profiler of idleness would be to place a profiler label
+  // frame with the IDLE category on the stack, for the duration of the function that does the
+  // waiting. However, since macOS uses an event loop model where "the event loop calls you", we do
+  // not control the function that does the waiting; the waiting happens inside CFRunLoop code.
+  // Instead, the run loop notifies us when it enters and exits the waiting state, by calling this
+  // function.
+  // So we do not have a function under our control that stays on the stack for the duration of the
+  // wait. So, rather than putting an AutoProfilerLabel on the stack, we will manually push and pop
+  // the label frame here.
+  // The location in the stack where this label frame is inserted is somewhat arbitrary. In
+  // practice, the label frame will be at the very tip of the stack, looking like it's "inside" the
+  // mach_msg_trap wait function.
+  if (aActivity == kCFRunLoopBeforeWaiting) {
+    using ThreadRegistration = mozilla::profiler::ThreadRegistration;
+    ThreadRegistration::WithOnThreadRef([&](ThreadRegistration::OnThreadRef aOnThreadRef) {
+      ProfilingStack& profilingStack =
+          aOnThreadRef.UnlockedConstReaderAndAtomicRWRef().ProfilingStackRef();
+      mProfilingStackWhileWaiting = &profilingStack;
+      uint8_t variableOnStack = 0;
+      profilingStack.pushLabelFrame("Native event loop idle", nullptr, &variableOnStack,
+                                    JS::ProfilingCategoryPair::IDLE, 0);
+      profiler_thread_sleep();
+    });
+  } else {
+    if (mProfilingStackWhileWaiting) {
+      mProfilingStackWhileWaiting->pop();
+      mProfilingStackWhileWaiting = nullptr;
+      profiler_thread_wake();
+    }
+  }
+}
+
+// Init
+//
+// Loads the nib (see bug 316076c21) and sets up the CFRunLoopSource used to
+// interrupt the main native run loop.
+//
+// public
+nsresult nsAppShell::Init() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // No event loop is running yet (unless an embedding app that uses
+  // NSApplicationMain() is running).
+  NSAutoreleasePool* localPool = [[NSAutoreleasePool alloc] init];
+
+  char* mozAppNoDock = PR_GetEnv("MOZ_APP_NO_DOCK");
+  if (mozAppNoDock && strcmp(mozAppNoDock, "") != 0) {
+    [NSApp setActivationPolicy:NSApplicationActivationPolicyAccessory];
+  }
+
+  // mAutoreleasePools is used as a stack of NSAutoreleasePool objects created
+  // by |this|.  CFArray is used instead of NSArray because NSArray wants to
+  // retain each object you add to it, and you can't retain an
+  // NSAutoreleasePool.
+  mAutoreleasePools = ::CFArrayCreateMutable(nullptr, 0, nullptr);
+  NS_ENSURE_STATE(mAutoreleasePools);
+
+  bool isNSApplicationProcessType = (XRE_GetProcessType() != GeckoProcessType_RDD) &&
+                                    (XRE_GetProcessType() != GeckoProcessType_Socket);
+
+  if (isNSApplicationProcessType) {
+    // This call initializes NSApplication unless:
+    // 1) we're using xre -- NSApp's already been initialized by
+    //    MacApplicationDelegate.mm's EnsureUseCocoaDockAPI().
+    // 2) an embedding app that uses NSApplicationMain() is running -- NSApp's
+    //    already been initialized and its main run loop is already running.
+    [[NSBundle mainBundle] loadNibNamed:@"res/MainMenu"
+                                  owner:[GeckoNSApplication sharedApplication]
+                        topLevelObjects:nil];
+  }
+
+  mDelegate = [[AppShellDelegate alloc] initWithAppShell:this];
+  NS_ENSURE_STATE(mDelegate);
+
+  // Add a CFRunLoopSource to the main native run loop.  The source is
+  // responsible for interrupting the run loop when Gecko events are ready.
+
+  mCFRunLoop = [[NSRunLoop currentRunLoop] getCFRunLoop];
+  NS_ENSURE_STATE(mCFRunLoop);
+  ::CFRetain(mCFRunLoop);
+
+  CFRunLoopSourceContext context;
+  bzero(&context, sizeof(context));
+  // context.version = 0;
+  context.info = this;
+  context.perform = ProcessGeckoEvents;
+
+  mCFRunLoopSource = ::CFRunLoopSourceCreate(kCFAllocatorDefault, 0, &context);
+  NS_ENSURE_STATE(mCFRunLoopSource);
+
+  ::CFRunLoopAddSource(mCFRunLoop, mCFRunLoopSource, kCFRunLoopCommonModes);
+
+  // Add a CFRunLoopObserver so that the profiler can be notified when we enter and exit the waiting
+  // state.
+  CFRunLoopObserverContext observerContext;
+  PodZero(&observerContext);
+  observerContext.info = this;
+
+  mCFRunLoopObserver = ::CFRunLoopObserverCreate(
+      kCFAllocatorDefault, kCFRunLoopBeforeWaiting | kCFRunLoopAfterWaiting | kCFRunLoopExit, true,
+      0, RunLoopObserverCallback, &observerContext);
+  NS_ENSURE_STATE(mCFRunLoopObserver);
+
+  ::CFRunLoopAddObserver(mCFRunLoop, mCFRunLoopObserver, kCFRunLoopCommonModes);
+
+  hal::Init();
+
+  if (XRE_IsParentProcess()) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+
+    if (gfxPlatform::IsHeadless()) {
+      screenManager.SetHelper(mozilla::MakeUnique<HeadlessScreenHelper>());
+    } else {
+      screenManager.SetHelper(mozilla::MakeUnique<ScreenHelperCocoa>());
+    }
+
+    InitMemoryPressureObserver();
+  }
+
+  nsresult rv = nsBaseAppShell::Init();
+
+  if (isNSApplicationProcessType && !gAppShellMethodsSwizzled) {
+    // We should only replace the original terminate: method if we're not
+    // running in a Cocoa embedder. See bug 604901.
+    if (!mRunningCocoaEmbedded) {
+      nsToolkit::SwizzleMethods([NSApplication class], @selector(terminate:),
+                                @selector(nsAppShell_NSApplication_terminate:));
+    }
+    gAppShellMethodsSwizzled = true;
+  }
+
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+  if (Preferences::GetBool("security.sandbox.mac.track.violations", false)) {
+    nsSandboxViolationSink::Start();
+  }
+#endif
+
+  [localPool release];
+
+  return rv;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// ProcessGeckoEvents
+//
+// The "perform" target of mCFRunLoop, called when mCFRunLoopSource is
+// signalled from ScheduleNativeEventCallback.
+//
+// Arrange for Gecko events to be processed on demand (in response to a call
+// to ScheduleNativeEventCallback(), if processing of Gecko events via "native
+// methods" hasn't been suspended).  This happens in NativeEventCallback().
+//
+// protected static
+void nsAppShell::ProcessGeckoEvents(void* aInfo) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  AUTO_PROFILER_LABEL("nsAppShell::ProcessGeckoEvents", OTHER);
+
+  nsAppShell* self = static_cast<nsAppShell*>(aInfo);
+
+  if (self->mRunningEventLoop) {
+    self->mRunningEventLoop = false;
+
+    // The run loop may be sleeping -- [NSRunLoop runMode:...]
+    // won't return until it's given a reason to wake up.  Awaken it by
+    // posting a bogus event.  There's no need to make the event
+    // presentable.
+    //
+    // But _don't_ set windowNumber to '-1' -- that can lead to nasty
+    // weirdness like bmo bug 397039 (a crash in [NSApp sendEvent:] on one of
+    // these fake events, because the -1 has gotten changed into the number
+    // of an actual NSWindow object, and that NSWindow object has just been
+    // destroyed).  Setting windowNumber to '0' seems to work fine -- this
+    // seems to prevent the OS from ever trying to associate our bogus event
+    // with a particular NSWindow object.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+    // Previously we used to send this second event regardless of
+    // self->mRunningEventLoop. However, that was removed in bug 1690687 for
+    // performance reasons. It is still needed for the mRunningEventLoop case
+    // otherwise we'll get in a cycle of sending postEvent followed by the
+    // DummyEvent inserted by nsBaseAppShell::OnProcessNextEvent. This second
+    // event will cause the second call to AcquireFirstMatchingEventInQueue in
+    // nsAppShell::ProcessNextNativeEvent to return true. Which makes
+    // nsBaseAppShell::OnProcessNextEvent call nsAppShell::ProcessNextNativeEvent
+    // again during which it will loop until it sleeps because ProcessGeckoEvents()
+    // won't be called for the DummyEvent.
+    //
+    // This is not a good approach and we should fix things up so that only
+    // one postEvent is needed.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+  }
+
+  if (self->mSuspendNativeCount <= 0) {
+    ++self->mNativeEventCallbackDepth;
+    self->NativeEventCallback();
+    --self->mNativeEventCallbackDepth;
+  } else {
+    self->mSkippedNativeCallback = true;
+  }
+
+  if (self->mTerminated) {
+    // Still needed to avoid crashes on quit in most Mochitests.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+  }
+  // Normally every call to ScheduleNativeEventCallback() results in
+  // exactly one call to ProcessGeckoEvents().  So each Release() here
+  // normally balances exactly one AddRef() in ScheduleNativeEventCallback().
+  // But if Exit() is called just after ScheduleNativeEventCallback(), the
+  // corresponding call to ProcessGeckoEvents() will never happen.  We check
+  // for this possibility in two different places -- here and in Exit()
+  // itself.  If we find here that Exit() has been called (that mTerminated
+  // is true), it's because we've been called recursively, that Exit() was
+  // called from self->NativeEventCallback() above, and that we're unwinding
+  // the recursion.  In this case we'll never be called again, and we balance
+  // here any extra calls to ScheduleNativeEventCallback().
+  //
+  // When ProcessGeckoEvents() is called recursively, it's because of a
+  // call to ScheduleNativeEventCallback() from NativeEventCallback().  We
+  // balance the "extra" AddRefs here (rather than always in Exit()) in order
+  // to ensure that 'self' stays alive until the end of this method.  We also
+  // make sure not to finish the balancing until all the recursion has been
+  // unwound.
+  if (self->mTerminated) {
+    int32_t releaseCount = 0;
+    if (self->mNativeEventScheduledDepth > self->mNativeEventCallbackDepth) {
+      releaseCount =
+          PR_ATOMIC_SET(&self->mNativeEventScheduledDepth, self->mNativeEventCallbackDepth);
+    }
+    while (releaseCount-- > self->mNativeEventCallbackDepth) self->Release();
+  } else {
+    // As best we can tell, every call to ProcessGeckoEvents() is triggered
+    // by a call to ScheduleNativeEventCallback().  But we've seen a few
+    // (non-reproducible) cases of double-frees that *might* have been caused
+    // by spontaneous calls (from the OS) to ProcessGeckoEvents().  So we
+    // deal with that possibility here.
+    if (PR_ATOMIC_DECREMENT(&self->mNativeEventScheduledDepth) < 0) {
+      PR_ATOMIC_SET(&self->mNativeEventScheduledDepth, 0);
+      NS_WARNING("Spontaneous call to ProcessGeckoEvents()!");
+    } else {
+      self->Release();
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// WillTerminate
+//
+// Called by the AppShellDelegate when an NSApplicationWillTerminate
+// notification is posted.  After this method is called, native events should
+// no longer be processed.  The NSApplicationWillTerminate notification is
+// only posted when [NSApp terminate:] is called, which doesn't happen on a
+// "normal" application quit.
+//
+// public
+void nsAppShell::WillTerminate() {
+  if (mTerminated) return;
+
+  // Make sure that the nsAppExitEvent posted by nsAppStartup::Quit() (called
+  // from [MacApplicationDelegate applicationShouldTerminate:]) gets run.
+  NS_ProcessPendingEvents(NS_GetCurrentThread());
+
+  mTerminated = true;
+}
+
+// ScheduleNativeEventCallback
+//
+// Called (possibly on a non-main thread) when Gecko has an event that
+// needs to be processed.  The Gecko event needs to be processed on the
+// main thread, so the native run loop must be interrupted.
+//
+// In nsBaseAppShell.cpp, the mNativeEventPending variable is used to
+// ensure that ScheduleNativeEventCallback() is called no more than once
+// per call to NativeEventCallback().  ProcessGeckoEvents() can skip its
+// call to NativeEventCallback() if processing of Gecko events by native
+// means is suspended (using nsIAppShell::SuspendNative()), which will
+// suspend calls from nsBaseAppShell::OnDispatchedEvent() to
+// ScheduleNativeEventCallback().  But when Gecko event processing by
+// native means is resumed (in ResumeNative()), an extra call is made to
+// ScheduleNativeEventCallback() (from ResumeNative()).  This triggers
+// another call to ProcessGeckoEvents(), which calls NativeEventCallback(),
+// and nsBaseAppShell::OnDispatchedEvent() resumes calling
+// ScheduleNativeEventCallback().
+//
+// protected virtual
+void nsAppShell::ScheduleNativeEventCallback() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mTerminated) return;
+
+  // Each AddRef() here is normally balanced by exactly one Release() in
+  // ProcessGeckoEvents().  But there are exceptions, for which see
+  // ProcessGeckoEvents() and Exit().
+  NS_ADDREF_THIS();
+  PR_ATOMIC_INCREMENT(&mNativeEventScheduledDepth);
+
+  // This will invoke ProcessGeckoEvents on the main thread.
+  ::CFRunLoopSourceSignal(mCFRunLoopSource);
+  ::CFRunLoopWakeUp(mCFRunLoop);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Undocumented Cocoa Event Manager function, present in the same form since
+// at least OS X 10.6.
+extern "C" EventAttributes GetEventAttributes(EventRef inEvent);
+
+// ProcessNextNativeEvent
+//
+// If aMayWait is false, process a single native event.  If it is true, run
+// the native run loop until stopped by ProcessGeckoEvents.
+//
+// Returns true if more events are waiting in the native event queue.
+//
+// protected virtual
+bool nsAppShell::ProcessNextNativeEvent(bool aMayWait) {
+  bool moreEvents = false;
+
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  bool eventProcessed = false;
+  NSString* currentMode = nil;
+
+  if (mTerminated) return false;
+
+  // Do not call -[NSApplication nextEventMatchingMask:...] when we're trying to close a native
+  // menu. Doing so could confuse the NSMenu's closing mechanism. Instead, we try to unwind the
+  // stack as quickly as possible and return to the parent event loop. At that point, native events
+  // will be processed.
+  if (MOZMenuOpeningCoordinator.needToUnwindForMenuClosing) {
+    return false;
+  }
+
+  bool wasRunningEventLoop = mRunningEventLoop;
+  mRunningEventLoop = aMayWait;
+  NSDate* waitUntil = nil;
+  if (aMayWait) waitUntil = [NSDate distantFuture];
+
+  NSRunLoop* currentRunLoop = [NSRunLoop currentRunLoop];
+
+  EventQueueRef currentEventQueue = GetCurrentEventQueue();
+
+  if (aMayWait) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+
+  // Only call -[NSApp sendEvent:] (and indirectly send user-input events to
+  // Gecko) if aMayWait is true.  Tbis ensures most calls to -[NSApp
+  // sendEvent:] happen under nsAppShell::Run(), at the lowest level of
+  // recursion -- thereby making it less likely Gecko will process user-input
+  // events in the wrong order or skip some of them.  It also avoids eating
+  // too much CPU in nsBaseAppShell::OnProcessNextEvent() (which calls
+  // us) -- thereby avoiding the starvation of nsIRunnable events in
+  // nsThread::ProcessNextEvent().  For more information see bug 996848.
+  do {
+    // No autorelease pool is provided here, because OnProcessNextEvent
+    // and AfterProcessNextEvent are responsible for maintaining it.
+    NS_ASSERTION(mAutoreleasePools && ::CFArrayGetCount(mAutoreleasePools),
+                 "No autorelease pool for native event");
+
+    if (aMayWait) {
+      currentMode = [currentRunLoop currentMode];
+      if (!currentMode) currentMode = NSDefaultRunLoopMode;
+      NSEvent* nextEvent = [NSApp nextEventMatchingMask:NSEventMaskAny
+                                              untilDate:waitUntil
+                                                 inMode:currentMode
+                                                dequeue:YES];
+      if (nextEvent) {
+        mozilla::BackgroundHangMonitor().NotifyActivity();
+        [NSApp sendEvent:nextEvent];
+        eventProcessed = true;
+      }
+    } else {
+      // In at least 10.15, AcquireFirstMatchingEventInQueue will move 1
+      // CGEvent from the CGEvent queue into the Carbon event queue. Unfortunately,
+      // once an event has been moved to the Carbon event queue it's no longer a
+      // candidate for coalescing. This means that even if we don't remove the
+      // event from the queue, just calling AcquireFirstMatchingEventInQueue can
+      // cause behaviour change. Prior to bug 1690687 landing, the event that we got
+      // from AcquireFirstMatchingEventInQueue was often our own ApplicationDefined
+      // event. However, once we stopped posting that event on every Gecko
+      // event we're much more likely to get a CGEvent. When we have a high
+      // amount of load on the main thread, we end up alternating between Gecko
+      // events and native events.  Without CGEvent coalescing, the native
+      // event events can accumulate in the Carbon event queue which will
+      // manifest as laggy scrolling.
+#if 1
+      eventProcessed = false;
+      break;
+#else
+      // AcquireFirstMatchingEventInQueue() doesn't spin the (native) event
+      // loop, though it does queue up any newly available events from the
+      // window server.
+      EventRef currentEvent =
+          AcquireFirstMatchingEventInQueue(currentEventQueue, 0, NULL, kEventQueueOptionsNone);
+      if (!currentEvent) {
+        continue;
+      }
+      EventAttributes attrs = GetEventAttributes(currentEvent);
+      UInt32 eventKind = GetEventKind(currentEvent);
+      UInt32 eventClass = GetEventClass(currentEvent);
+      bool osCocoaEvent =
+          ((eventClass == 'appl') || (eventClass == kEventClassAppleEvent) ||
+           ((eventClass == 'cgs ') && (eventKind != NSEventTypeApplicationDefined)));
+      // If attrs is kEventAttributeUserEvent or kEventAttributeMonitored
+      // (i.e. a user input event), we shouldn't process it here while
+      // aMayWait is false.  Likewise if currentEvent will eventually be
+      // turned into an OS-defined Cocoa event, or otherwise needs AppKit
+      // processing.  Doing otherwise risks doing too much work here, and
+      // preventing the event from being properly processed by the AppKit
+      // framework.
+      if ((attrs != kEventAttributeNone) || osCocoaEvent) {
+        // Since we can't process the next event here (while aMayWait is false),
+        // we want moreEvents to be false on return.
+        eventProcessed = false;
+        // This call to ReleaseEvent() matches a call to RetainEvent() in
+        // AcquireFirstMatchingEventInQueue() above.
+        ReleaseEvent(currentEvent);
+        break;
+      }
+      // This call to RetainEvent() matches a call to ReleaseEvent() in
+      // RemoveEventFromQueue() below.
+      RetainEvent(currentEvent);
+      RemoveEventFromQueue(currentEventQueue, currentEvent);
+      EventTargetRef eventDispatcherTarget = GetEventDispatcherTarget();
+      SendEventToEventTarget(currentEvent, eventDispatcherTarget);
+      // This call to ReleaseEvent() matches a call to RetainEvent() in
+      // AcquireFirstMatchingEventInQueue() above.
+      ReleaseEvent(currentEvent);
+      eventProcessed = true;
+#endif
+    }
+  } while (mRunningEventLoop);
+
+  if (eventProcessed) {
+    moreEvents = (AcquireFirstMatchingEventInQueue(currentEventQueue, 0, NULL,
+                                                   kEventQueueOptionsNone) != NULL);
+  }
+
+  mRunningEventLoop = wasRunningEventLoop;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+
+  if (!moreEvents) {
+    nsChildView::UpdateCurrentInputEventCount();
+  }
+
+  return moreEvents;
+}
+
+// Attempt to work around bug 1801419 by loading and initializing the
+// SidecarCore private framework as the app shell starts up. This normally
+// happens on demand, the first time any Cmd-key combination is pressed, and
+// sometimes triggers crashes, caused by an Apple bug. We hope that doing it
+// now, and somewhat more simply, will avoid the crashes. They happen
+// (intermittently) when SidecarCore code tries to access C strings in special
+// sections of its own __TEXT segment, and triggers fatal page faults (which
+// is Apple's bug). Many of the C strings are part of the Objective-C class
+// hierarchy (class names and so forth). We hope that adding them to this
+// hierarchy will "pin" them in place -- so they'll rarely, if ever, be paged
+// out again. Bug 1801419's crashes happen much more often on macOS 13
+// (Ventura) than on other versions of macOS. So we only use this hack on
+// macOS 13 and up.
+static void PinSidecarCoreTextCStringSections() {
+  if (!dlopen("/System/Library/PrivateFrameworks/SidecarCore.framework/SidecarCore", RTLD_LAZY)) {
+    return;
+  }
+
+  // Explicitly run the most basic part of the initialization code that
+  // normally runs automatically on the first Cmd-key combination.
+  Class displayManagerClass = NSClassFromString(@"SidecarDisplayManager");
+  if ([displayManagerClass respondsToSelector:@selector(sharedManager)]) {
+    id sharedManager = [displayManagerClass performSelector:@selector(sharedManager)];
+    if ([sharedManager respondsToSelector:@selector(devices)]) {
+      [sharedManager performSelector:@selector(devices)];
+    }
+  }
+}
+
+// Run
+//
+// Overrides the base class's Run() method to call [NSApp run] (which spins
+// the native run loop until the application quits).  Since (unlike the base
+// class's Run() method) we don't process any Gecko events here, they need
+// to be processed elsewhere (in NativeEventCallback(), called from
+// ProcessGeckoEvents()).
+//
+// Camino called [NSApp run] on its own (via NSApplicationMain()), and so
+// didn't call nsAppShell::Run().
+//
+// public
+NS_IMETHODIMP
+nsAppShell::Run(void) {
+  NS_ASSERTION(!mStarted, "nsAppShell::Run() called multiple times");
+  if (mStarted || mTerminated) return NS_OK;
+
+  mStarted = true;
+
+  if (XRE_IsParentProcess()) {
+    if (nsCocoaFeatures::OnVenturaOrLater()) {
+      PinSidecarCoreTextCStringSections();
+    }
+    AddScreenWakeLockListener();
+  }
+
+  // We use the native Gecko event loop in content processes.
+  nsresult rv = NS_OK;
+  if (XRE_UseNativeEventProcessing()) {
+    NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+    [NSApp run];
+    NS_OBJC_END_TRY_IGNORE_BLOCK;
+  } else {
+    rv = nsBaseAppShell::Run();
+  }
+
+  if (XRE_IsParentProcess()) {
+    RemoveScreenWakeLockListener();
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAppShell::Exit(void) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // This method is currently called more than once -- from (according to
+  // mento) an nsAppExitEvent dispatched by nsAppStartup::Quit() and from an
+  // XPCOM shutdown notification that nsBaseAppShell has registered to
+  // receive.  So we need to ensure that multiple calls won't break anything.
+  // But we should also complain about it (since it isn't quite kosher).
+  if (mTerminated) {
+    NS_WARNING("nsAppShell::Exit() called redundantly");
+    return NS_OK;
+  }
+
+  mTerminated = true;
+
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+  nsSandboxViolationSink::Stop();
+#endif
+
+  // Quoting from Apple's doc on the [NSApplication stop:] method (from their
+  // doc on the NSApplication class):  "If this method is invoked during a
+  // modal event loop, it will break that loop but not the main event loop."
+  // nsAppShell::Exit() shouldn't be called from a modal event loop.  So if
+  // it is we complain about it (to users of debug builds) and call [NSApp
+  // stop:] one extra time.  (I'm not sure if modal event loops can be nested
+  // -- Apple's docs don't say one way or the other.  But the return value
+  // of [NSApp _isRunningModal] doesn't change immediately after a call to
+  // [NSApp stop:], so we have to assume that one extra call to [NSApp stop:]
+  // will do the job.)
+  BOOL cocoaModal = [NSApp _isRunningModal];
+  NS_ASSERTION(!cocoaModal, "Don't call nsAppShell::Exit() from a modal event loop!");
+  if (cocoaModal) [NSApp stop:nullptr];
+  [NSApp stop:nullptr];
+
+  // A call to Exit() just after a call to ScheduleNativeEventCallback()
+  // prevents the (normally) matching call to ProcessGeckoEvents() from
+  // happening.  If we've been called from ProcessGeckoEvents() (as usually
+  // happens), we take care of it there.  But if we have an unbalanced call
+  // to ScheduleNativeEventCallback() and ProcessGeckoEvents() isn't on the
+  // stack, we need to take care of the problem here.
+  if (!mNativeEventCallbackDepth && mNativeEventScheduledDepth) {
+    int32_t releaseCount = PR_ATOMIC_SET(&mNativeEventScheduledDepth, 0);
+    while (releaseCount-- > 0) NS_RELEASE_THIS();
+  }
+
+  return nsBaseAppShell::Exit();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// OnProcessNextEvent
+//
+// This nsIThreadObserver method is called prior to processing an event.
+// Set up an autorelease pool that will service any autoreleased Cocoa
+// objects during this event.  This includes native events processed by
+// ProcessNextNativeEvent.  The autorelease pool will be popped by
+// AfterProcessNextEvent, it is important for these two methods to be
+// tightly coupled.
+//
+// public
+NS_IMETHODIMP
+nsAppShell::OnProcessNextEvent(nsIThreadInternal* aThread, bool aMayWait) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ASSERTION(mAutoreleasePools, "No stack on which to store autorelease pool");
+
+  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+  ::CFArrayAppendValue(mAutoreleasePools, pool);
+
+  return nsBaseAppShell::OnProcessNextEvent(aThread, aMayWait);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// AfterProcessNextEvent
+//
+// This nsIThreadObserver method is called after event processing is complete.
+// The Cocoa implementation cleans up the autorelease pool create by the
+// previous OnProcessNextEvent call.
+//
+// public
+NS_IMETHODIMP
+nsAppShell::AfterProcessNextEvent(nsIThreadInternal* aThread, bool aEventWasProcessed) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  CFIndex count = ::CFArrayGetCount(mAutoreleasePools);
+
+  NS_ASSERTION(mAutoreleasePools && count, "Processed an event, but there's no autorelease pool?");
+
+  const NSAutoreleasePool* pool =
+      static_cast<const NSAutoreleasePool*>(::CFArrayGetValueAtIndex(mAutoreleasePools, count - 1));
+  ::CFArrayRemoveValueAtIndex(mAutoreleasePools, count - 1);
+  [pool release];
+
+  return nsBaseAppShell::AfterProcessNextEvent(aThread, aEventWasProcessed);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsAppShell::InitMemoryPressureObserver() {
+  // Testing shows that sometimes the memory pressure event is not fired for
+  // over a minute after the memory pressure change is reflected in sysctl
+  // values. Hence this may need to be augmented with polling of the memory
+  // pressure sysctls for lower latency reactions to OS memory pressure. This
+  // was also observed when using DISPATCH_QUEUE_PRIORITY_HIGH.
+  mMemoryPressureSource =
+      dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0,
+                             DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN |
+                                 DISPATCH_MEMORYPRESSURE_CRITICAL,
+                             dispatch_get_main_queue());
+
+  dispatch_source_set_event_handler(mMemoryPressureSource, ^{
+    dispatch_source_memorypressure_flags_t pressureLevel =
+        dispatch_source_get_data(mMemoryPressureSource);
+    nsAppShell::OnMemoryPressureChanged(pressureLevel);
+  });
+
+  dispatch_resume(mMemoryPressureSource);
+
+  // Initialize the memory watcher.
+  RefPtr<mozilla::nsAvailableMemoryWatcherBase> watcher(
+      nsAvailableMemoryWatcherBase::GetSingleton());
+}
+
+void nsAppShell::OnMemoryPressureChanged(dispatch_source_memorypressure_flags_t aPressureLevel) {
+  // The memory pressure dispatch source is created (above) with
+  // dispatch_get_main_queue() which always fires on the main thread.
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MacMemoryPressureLevel geckoPressureLevel;
+  switch (aPressureLevel) {
+    case DISPATCH_MEMORYPRESSURE_NORMAL:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eNormal;
+      break;
+    case DISPATCH_MEMORYPRESSURE_WARN:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eWarning;
+      break;
+    case DISPATCH_MEMORYPRESSURE_CRITICAL:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eCritical;
+      break;
+    default:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eUnexpected;
+  }
+
+  RefPtr<mozilla::nsAvailableMemoryWatcherBase> watcher(
+      nsAvailableMemoryWatcherBase::GetSingleton());
+  watcher->OnMemoryPressureChanged(geckoPressureLevel);
+}
+
+// AppShellDelegate implementation
+
+@implementation AppShellDelegate
+// initWithAppShell:
+//
+// Constructs the AppShellDelegate object
+- (id)initWithAppShell:(nsAppShell*)aAppShell {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [self init])) {
+    mAppShell = aAppShell;
+
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationWillTerminate:)
+                                                 name:NSApplicationWillTerminateNotification
+                                               object:NSApp];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationDidBecomeActive:)
+                                                 name:NSApplicationDidBecomeActiveNotification
+                                               object:NSApp];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(timezoneChanged:)
+                                                 name:NSSystemTimeZoneDidChangeNotification
+                                               object:nil];
+  }
+
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [[NSDistributedNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// applicationWillTerminate:
+//
+// Notify the nsAppShell that native event processing should be discontinued.
+- (void)applicationWillTerminate:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mAppShell->WillTerminate();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// applicationDidBecomeActive
+//
+// Make sure TextInputHandler::sLastModifierState is updated when we become
+// active (since we won't have received [ChildView flagsChanged:] messages
+// while inactive).
+- (void)applicationDidBecomeActive:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // [NSEvent modifierFlags] is valid on every kind of event, so we don't need
+  // to worry about getting an NSInternalInconsistencyException here.
+  NSEvent* currentEvent = [NSApp currentEvent];
+  if (currentEvent) {
+    TextInputHandler::sLastModifierState =
+        [currentEvent modifierFlags] & NSEventModifierFlagDeviceIndependentFlagsMask;
+  }
+
+  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
+  if (observerService) {
+    observerService->NotifyObservers(nullptr, NS_WIDGET_MAC_APP_ACTIVATE_OBSERVER_TOPIC, nullptr);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)timezoneChanged:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  nsBaseAppShell::OnSystemTimezoneChange();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (BOOL)shouldSaveApplicationState:(NSCoder*)coder {
+  return YES;
+}
+
+- (BOOL)shouldRestoreApplicationState:(NSCoder*)coder {
+  return YES;
+}
+
+@end
+
+// We hook terminate: in order to make OS-initiated termination work nicely
+// with Gecko's shutdown sequence.  (Two ways to trigger OS-initiated
+// termination:  1) Quit from the Dock menu; 2) Log out from (or shut down)
+// your computer while the browser is active.)
+@interface NSApplication (MethodSwizzling)
+- (void)nsAppShell_NSApplication_terminate:(id)sender;
+@end
+
+@implementation NSApplication (MethodSwizzling)
+
+// Called by the OS after [MacApplicationDelegate applicationShouldTerminate:]
+// has returned NSTerminateNow.  This method "subclasses" and replaces the
+// OS's original implementation.  The only thing the orginal method does which
+// we need is that it posts NSApplicationWillTerminateNotification.  Everything
+// else is unneeded (because it's handled elsewhere), or actively interferes
+// with Gecko's shutdown sequence.  For example the original terminate: method
+// causes the app to exit() inside [NSApp run] (called from nsAppShell::Run()
+// above), which means that nothing runs after the call to nsAppStartup::Run()
+// in XRE_Main(), which in particular means that ScopedXPCOMStartup's destructor
+// and NS_ShutdownXPCOM() never get called.
+- (void)nsAppShell_NSApplication_terminate:(id)sender {
+  [[NSNotificationCenter defaultCenter] postNotificationName:NSApplicationWillTerminateNotification
+                                                      object:NSApp];
+}
+
+@end