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, 625 insertions, 0 deletions

diff --git a/widget/headless/HeadlessWidget.cpp b/widget/headless/HeadlessWidget.cpp
new file mode 100644
index 0000000000..083d026d3c
--- /dev/null
+++ b/widget/headless/HeadlessWidget.cpp
@@ -0,0 +1,625 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * 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/. */
+#include "HeadlessWidget.h"
+#include "ErrorList.h"
+#include "HeadlessCompositorWidget.h"
+#include "BasicEvents.h"
+#include "MouseEvents.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/widget/HeadlessWidgetTypes.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "mozilla/widget/Screen.h"
+#include "nsIScreen.h"
+#include "HeadlessKeyBindings.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+
+using mozilla::LogLevel;
+
+#ifdef MOZ_LOGGING
+
+#  include "mozilla/Logging.h"
+static mozilla::LazyLogModule sWidgetLog("Widget");
+static mozilla::LazyLogModule sWidgetFocusLog("WidgetFocus");
+#  define LOG(args) MOZ_LOG(sWidgetLog, mozilla::LogLevel::Debug, args)
+#  define LOGFOCUS(args) \
+    MOZ_LOG(sWidgetFocusLog, mozilla::LogLevel::Debug, args)
+
+#else
+
+#  define LOG(args)
+#  define LOGFOCUS(args)
+
+#endif /* MOZ_LOGGING */
+
+/*static*/
+already_AddRefed<nsIWidget> nsIWidget::CreateHeadlessWidget() {
+  nsCOMPtr<nsIWidget> widget = new mozilla::widget::HeadlessWidget();
+  return widget.forget();
+}
+
+namespace mozilla {
+namespace widget {
+
+StaticAutoPtr<nsTArray<HeadlessWidget*>> HeadlessWidget::sActiveWindows;
+
+already_AddRefed<HeadlessWidget> HeadlessWidget::GetActiveWindow() {
+  if (!sActiveWindows) {
+    return nullptr;
+  }
+  auto length = sActiveWindows->Length();
+  if (length == 0) {
+    return nullptr;
+  }
+  RefPtr<HeadlessWidget> widget = sActiveWindows->ElementAt(length - 1);
+  return widget.forget();
+}
+
+HeadlessWidget::HeadlessWidget()
+    : mEnabled(true),
+      mVisible(false),
+      mDestroyed(false),
+      mAlwaysOnTop(false),
+      mTopLevel(nullptr),
+      mCompositorWidget(nullptr),
+      mSizeMode(nsSizeMode_Normal),
+      mLastSizeMode(nsSizeMode_Normal),
+      mEffectiveSizeMode(nsSizeMode_Normal),
+      mRestoreBounds(0, 0, 0, 0) {
+  if (!sActiveWindows) {
+    sActiveWindows = new nsTArray<HeadlessWidget*>();
+    ClearOnShutdown(&sActiveWindows);
+  }
+}
+
+HeadlessWidget::~HeadlessWidget() {
+  LOG(("HeadlessWidget::~HeadlessWidget() [%p]\n", (void*)this));
+
+  Destroy();
+}
+
+void HeadlessWidget::Destroy() {
+  if (mDestroyed) {
+    return;
+  }
+  LOG(("HeadlessWidget::Destroy [%p]\n", (void*)this));
+  mDestroyed = true;
+
+  if (sActiveWindows) {
+    int32_t index = sActiveWindows->IndexOf(this);
+    if (index != -1) {
+      RefPtr<HeadlessWidget> activeWindow = GetActiveWindow();
+      sActiveWindows->RemoveElementAt(index);
+      // If this is the currently active widget and there's a previously active
+      // widget, activate the previous widget.
+      RefPtr<HeadlessWidget> previousActiveWindow = GetActiveWindow();
+      if (this == activeWindow && previousActiveWindow &&
+          previousActiveWindow->mWidgetListener) {
+        previousActiveWindow->mWidgetListener->WindowActivated();
+      }
+    }
+  }
+
+  nsBaseWidget::OnDestroy();
+
+  nsBaseWidget::Destroy();
+}
+
+nsresult HeadlessWidget::Create(nsIWidget* aParent,
+                                nsNativeWidget aNativeParent,
+                                const LayoutDeviceIntRect& aRect,
+                                widget::InitData* aInitData) {
+  MOZ_ASSERT(!aNativeParent, "No native parents for headless widgets.");
+
+  BaseCreate(nullptr, aInitData);
+
+  mBounds = aRect;
+  mRestoreBounds = aRect;
+
+  mAlwaysOnTop = aInitData && aInitData->mAlwaysOnTop;
+
+  if (aParent) {
+    mTopLevel = aParent->GetTopLevelWidget();
+  } else {
+    mTopLevel = this;
+  }
+
+  return NS_OK;
+}
+
+already_AddRefed<nsIWidget> HeadlessWidget::CreateChild(
+    const LayoutDeviceIntRect& aRect, widget::InitData* aInitData,
+    bool aForceUseIWidgetParent) {
+  nsCOMPtr<nsIWidget> widget = nsIWidget::CreateHeadlessWidget();
+  if (!widget) {
+    return nullptr;
+  }
+  if (NS_FAILED(widget->Create(this, nullptr, aRect, aInitData))) {
+    return nullptr;
+  }
+  return widget.forget();
+}
+
+void HeadlessWidget::GetCompositorWidgetInitData(
+    mozilla::widget::CompositorWidgetInitData* aInitData) {
+  *aInitData =
+      mozilla::widget::HeadlessCompositorWidgetInitData(GetClientSize());
+}
+
+nsIWidget* HeadlessWidget::GetTopLevelWidget() { return mTopLevel; }
+
+void HeadlessWidget::RaiseWindow() {
+  MOZ_ASSERT(mWindowType == WindowType::TopLevel ||
+                 mWindowType == WindowType::Dialog ||
+                 mWindowType == WindowType::Sheet,
+             "Raising a non-toplevel window.");
+
+  // Do nothing if this is the currently active window.
+  RefPtr<HeadlessWidget> activeWindow = GetActiveWindow();
+  if (activeWindow == this) {
+    return;
+  }
+
+  // Raise the window to the top of the stack.
+  nsWindowZ placement = nsWindowZTop;
+  nsCOMPtr<nsIWidget> actualBelow;
+  if (mWidgetListener)
+    mWidgetListener->ZLevelChanged(true, &placement, nullptr,
+                                   getter_AddRefs(actualBelow));
+
+  // Deactivate the last active window.
+  if (activeWindow && activeWindow->mWidgetListener) {
+    activeWindow->mWidgetListener->WindowDeactivated();
+  }
+
+  // Remove this window if it's already tracked.
+  int32_t index = sActiveWindows->IndexOf(this);
+  if (index != -1) {
+    sActiveWindows->RemoveElementAt(index);
+  }
+
+  // Activate this window.
+  sActiveWindows->AppendElement(this);
+  if (mWidgetListener) mWidgetListener->WindowActivated();
+}
+
+void HeadlessWidget::Show(bool aState) {
+  mVisible = aState;
+
+  LOG(("HeadlessWidget::Show [%p] state %d\n", (void*)this, aState));
+
+  // Top-level window and dialogs are activated/raised when shown.
+  // NB: alwaysontop windows are generally used for peripheral indicators,
+  //     so we don't focus them by default.
+  if (aState && !mAlwaysOnTop &&
+      (mWindowType == WindowType::TopLevel ||
+       mWindowType == WindowType::Dialog || mWindowType == WindowType::Sheet)) {
+    RaiseWindow();
+  }
+
+  ApplySizeModeSideEffects();
+}
+
+bool HeadlessWidget::IsVisible() const { return mVisible; }
+
+void HeadlessWidget::SetFocus(Raise aRaise,
+                              mozilla::dom::CallerType aCallerType) {
+  LOGFOCUS(("  SetFocus %d [%p]\n", aRaise == Raise::Yes, (void*)this));
+
+  // This means we request activation of our toplevel window.
+  if (aRaise == Raise::Yes) {
+    HeadlessWidget* topLevel = (HeadlessWidget*)GetTopLevelWidget();
+
+    // The toplevel only becomes active if it's currently visible; otherwise, it
+    // will be activated anyway when it's shown.
+    if (topLevel->IsVisible()) topLevel->RaiseWindow();
+  }
+}
+
+void HeadlessWidget::Enable(bool aState) { mEnabled = aState; }
+
+bool HeadlessWidget::IsEnabled() const { return mEnabled; }
+
+void HeadlessWidget::Move(double aX, double aY) {
+  LOG(("HeadlessWidget::Move [%p] %f %f\n", (void*)this, aX, aY));
+
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t x = NSToIntRound(aX * scale);
+  int32_t y = NSToIntRound(aY * scale);
+
+  if (mWindowType == WindowType::TopLevel ||
+      mWindowType == WindowType::Dialog) {
+    SetSizeMode(nsSizeMode_Normal);
+  }
+
+  MoveInternal(x, y);
+}
+
+void HeadlessWidget::MoveInternal(int32_t aX, int32_t aY) {
+  // Since a popup window's x/y coordinates are in relation to
+  // the parent, the parent might have moved so we always move a
+  // popup window.
+  if (mBounds.IsEqualXY(aX, aY) && mWindowType != WindowType::Popup) {
+    return;
+  }
+
+  mBounds.MoveTo(aX, aY);
+  NotifyWindowMoved(aX, aY);
+}
+
+LayoutDeviceIntPoint HeadlessWidget::WidgetToScreenOffset() {
+  return mTopLevel->GetBounds().TopLeft();
+}
+
+WindowRenderer* HeadlessWidget::GetWindowRenderer() {
+  return nsBaseWidget::GetWindowRenderer();
+}
+
+void HeadlessWidget::SetCompositorWidgetDelegate(
+    CompositorWidgetDelegate* delegate) {
+  if (delegate) {
+    mCompositorWidget = delegate->AsHeadlessCompositorWidget();
+    MOZ_ASSERT(mCompositorWidget,
+               "HeadlessWidget::SetCompositorWidgetDelegate called with a "
+               "non-HeadlessCompositorWidget");
+  } else {
+    mCompositorWidget = nullptr;
+  }
+}
+
+void HeadlessWidget::Resize(double aWidth, double aHeight, bool aRepaint) {
+  int32_t width = NSToIntRound(aWidth);
+  int32_t height = NSToIntRound(aHeight);
+  ResizeInternal(width, height, aRepaint);
+}
+
+void HeadlessWidget::ResizeInternal(int32_t aWidth, int32_t aHeight,
+                                    bool aRepaint) {
+  ConstrainSize(&aWidth, &aHeight);
+  mBounds.SizeTo(LayoutDeviceIntSize(aWidth, aHeight));
+
+  if (mCompositorWidget) {
+    mCompositorWidget->NotifyClientSizeChanged(
+        LayoutDeviceIntSize(mBounds.Width(), mBounds.Height()));
+  }
+  if (mWidgetListener) {
+    mWidgetListener->WindowResized(this, mBounds.Width(), mBounds.Height());
+  }
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->WindowResized(this, mBounds.Width(),
+                                           mBounds.Height());
+  }
+}
+
+void HeadlessWidget::Resize(double aX, double aY, double aWidth, double aHeight,
+                            bool aRepaint) {
+  MoveInternal(NSToIntRound(aX), NSToIntRound(aY));
+  Resize(aWidth, aHeight, aRepaint);
+}
+
+void HeadlessWidget::SetSizeMode(nsSizeMode aMode) {
+  LOG(("HeadlessWidget::SetSizeMode [%p] %d\n", (void*)this, aMode));
+
+  if (aMode == mSizeMode) {
+    return;
+  }
+
+  if (aMode == nsSizeMode_Normal && mSizeMode == nsSizeMode_Fullscreen) {
+    MakeFullScreen(false);
+    return;
+  }
+
+  mSizeMode = aMode;
+
+  // Normally in real widget backends a window event would be triggered that
+  // would cause the window manager to handle resizing the window. In headless
+  // the window must manually be resized.
+  ApplySizeModeSideEffects();
+}
+
+void HeadlessWidget::ApplySizeModeSideEffects() {
+  if (!mVisible || mEffectiveSizeMode == mSizeMode) {
+    return;
+  }
+
+  if (mEffectiveSizeMode == nsSizeMode_Normal) {
+    // Store the last normal size bounds so it can be restored when entering
+    // normal mode again.
+    mRestoreBounds = mBounds;
+  }
+
+  switch (mSizeMode) {
+    case nsSizeMode_Normal: {
+      MoveInternal(mRestoreBounds.X(), mRestoreBounds.Y());
+      ResizeInternal(mRestoreBounds.Width(), mRestoreBounds.Height(), false);
+      break;
+    }
+    case nsSizeMode_Minimized:
+      break;
+    case nsSizeMode_Maximized: {
+      nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+      if (screen) {
+        int32_t left, top, width, height;
+        if (NS_SUCCEEDED(
+                screen->GetRectDisplayPix(&left, &top, &width, &height))) {
+          MoveInternal(0, 0);
+          ResizeInternal(width, height, true);
+        }
+      }
+      break;
+    }
+    case nsSizeMode_Fullscreen:
+      // This will take care of resizing the window.
+      nsBaseWidget::InfallibleMakeFullScreen(true);
+      break;
+    default:
+      break;
+  }
+
+  mEffectiveSizeMode = mSizeMode;
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(mSizeMode);
+  }
+}
+
+nsresult HeadlessWidget::MakeFullScreen(bool aFullScreen) {
+  // Directly update the size mode here so a later call SetSizeMode does
+  // nothing.
+  if (aFullScreen) {
+    if (mSizeMode != nsSizeMode_Fullscreen) {
+      mLastSizeMode = mSizeMode;
+    }
+    mSizeMode = nsSizeMode_Fullscreen;
+  } else {
+    mSizeMode = mLastSizeMode;
+  }
+
+  // Notify the listener first so size mode change events are triggered before
+  // resize events.
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(mSizeMode);
+  }
+
+  // Real widget backends don't seem to follow a common approach for
+  // when and how many resize events are triggered during fullscreen
+  // transitions. InfallibleMakeFullScreen will trigger a resize, but it
+  // will be ignored if still transitioning to fullscreen, so it must be
+  // triggered on the next tick.
+  RefPtr<HeadlessWidget> self(this);
+  NS_DispatchToCurrentThread(NS_NewRunnableFunction(
+      "HeadlessWidget::MakeFullScreen", [self, aFullScreen]() -> void {
+        self->InfallibleMakeFullScreen(aFullScreen);
+      }));
+
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::AttachNativeKeyEvent(WidgetKeyboardEvent& aEvent) {
+  HeadlessKeyBindings& bindings = HeadlessKeyBindings::GetInstance();
+  return bindings.AttachNativeKeyEvent(aEvent);
+}
+
+bool HeadlessWidget::GetEditCommands(NativeKeyBindingsType aType,
+                                     const WidgetKeyboardEvent& aEvent,
+                                     nsTArray<CommandInt>& aCommands) {
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+
+  Maybe<WritingMode> writingMode;
+  if (aEvent.NeedsToRemapNavigationKey()) {
+    if (RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher()) {
+      writingMode = dispatcher->MaybeQueryWritingModeAtSelection();
+    }
+  }
+
+  HeadlessKeyBindings& bindings = HeadlessKeyBindings::GetInstance();
+  bindings.GetEditCommands(aType, aEvent, writingMode, aCommands);
+  return true;
+}
+
+nsresult HeadlessWidget::DispatchEvent(WidgetGUIEvent* aEvent,
+                                       nsEventStatus& aStatus) {
+#ifdef DEBUG
+  debug_DumpEvent(stdout, aEvent->mWidget, aEvent, "HeadlessWidget", 0);
+#endif
+
+  aStatus = nsEventStatus_eIgnore;
+
+  if (mAttachedWidgetListener) {
+    aStatus = mAttachedWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  } else if (mWidgetListener) {
+    aStatus = mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  }
+
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+  EventMessage msg;
+  switch (aNativeMessage) {
+    case NativeMouseMessage::Move:
+      msg = eMouseMove;
+      break;
+    case NativeMouseMessage::ButtonDown:
+      msg = eMouseDown;
+      break;
+    case NativeMouseMessage::ButtonUp:
+      msg = eMouseUp;
+      break;
+    case NativeMouseMessage::EnterWindow:
+    case NativeMouseMessage::LeaveWindow:
+      MOZ_ASSERT_UNREACHABLE("Unsupported synthesized mouse event");
+      return NS_ERROR_UNEXPECTED;
+  }
+  WidgetMouseEvent event(true, msg, this, WidgetMouseEvent::eReal);
+  event.mRefPoint = aPoint - WidgetToScreenOffset();
+  if (msg == eMouseDown || msg == eMouseUp) {
+    event.mButton = aButton;
+  }
+  if (msg == eMouseDown) {
+    event.mClickCount = 1;
+  }
+  event.AssignEventTime(WidgetEventTime());
+  DispatchInputEvent(&event);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeMouseScrollEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage,
+    double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+  printf(">>> DEBUG_ME: Synth: aDeltaY=%f\n", aDeltaY);
+  // The various platforms seem to handle scrolling deltas differently,
+  // but the following seems to emulate it well enough.
+  WidgetWheelEvent event(true, eWheel, this);
+  event.mDeltaMode = MOZ_HEADLESS_SCROLL_DELTA_MODE;
+  event.mIsNoLineOrPageDelta = true;
+  event.mDeltaX = -aDeltaX * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mDeltaY = -aDeltaY * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mDeltaZ = -aDeltaZ * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mRefPoint = aPoint - WidgetToScreenOffset();
+  event.AssignEventTime(WidgetEventTime());
+  DispatchInputEvent(&event);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchPoint(
+    uint32_t aPointerId, TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPointerPressure,
+    uint32_t aPointerOrientation, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  MOZ_ASSERT(NS_IsMainThread());
+  if (aPointerState == TOUCH_HOVER) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (!mSynthesizedTouchInput) {
+    mSynthesizedTouchInput = MakeUnique<MultiTouchInput>();
+  }
+
+  LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+  MultiTouchInput inputToDispatch = UpdateSynthesizedTouchState(
+      mSynthesizedTouchInput.get(), TimeStamp::Now(), aPointerId, aPointerState,
+      pointInWindow, aPointerPressure, aPointerOrientation);
+  DispatchTouchInput(inputToDispatch);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchPadPinch(
+    TouchpadGesturePhase aEventPhase, float aScale, LayoutDeviceIntPoint aPoint,
+    int32_t aModifierFlags) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  PinchGestureInput::PinchGestureType pinchGestureType =
+      PinchGestureInput::PINCHGESTURE_SCALE;
+  ScreenCoord CurrentSpan;
+  ScreenCoord PreviousSpan;
+  switch (aEventPhase) {
+    case PHASE_BEGIN:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_START;
+      CurrentSpan = aScale;
+      PreviousSpan = 0.999;
+      break;
+
+    case PHASE_UPDATE:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+      if (aScale == mLastPinchSpan) {
+        return NS_ERROR_INVALID_ARG;
+      }
+      CurrentSpan = aScale;
+      PreviousSpan = mLastPinchSpan;
+      break;
+
+    case PHASE_END:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_END;
+      CurrentSpan = aScale;
+      PreviousSpan = mLastPinchSpan;
+      break;
+
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  ScreenPoint touchpadPoint = ViewAs<ScreenPixel>(
+      aPoint - WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  // The headless widget does not support modifiers.
+  // Do not pass `aModifierFlags` because it contains native modifier values.
+  PinchGestureInput inputToDispatch(
+      pinchGestureType, PinchGestureInput::TRACKPAD, TimeStamp::Now(),
+      ExternalPoint(0, 0), touchpadPoint,
+      100.0 * ((aEventPhase == PHASE_END) ? ScreenCoord(1.f) : CurrentSpan),
+      100.0 * ((aEventPhase == PHASE_END) ? ScreenCoord(1.f) : PreviousSpan),
+      0);
+
+  if (!inputToDispatch.SetLineOrPageDeltaY(this)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  mLastPinchSpan = aScale;
+  DispatchPinchGestureInput(inputToDispatch);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchpadPan(
+    TouchpadGesturePhase aEventPhase, LayoutDeviceIntPoint aPoint,
+    double aDeltaX, double aDeltaY, int32_t aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpadpanevent");
+
+  MOZ_ASSERT(NS_IsMainThread());
+
+  PanGestureInput::PanGestureType eventType = PanGestureInput::PANGESTURE_PAN;
+  switch (aEventPhase) {
+    case PHASE_BEGIN:
+      eventType = PanGestureInput::PANGESTURE_START;
+      break;
+    case PHASE_UPDATE:
+      eventType = PanGestureInput::PANGESTURE_PAN;
+      break;
+    case PHASE_END:
+      eventType = PanGestureInput::PANGESTURE_END;
+      break;
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  ScreenPoint touchpadPoint = ViewAs<ScreenPixel>(
+      aPoint - WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  PanGestureInput input(eventType, TimeStamp::Now(), touchpadPoint,
+                        ScreenPoint(float(aDeltaX), float(aDeltaY)),
+                        // Same as SynthesizeNativeTouchPadPinch case we ignore
+                        // aModifierFlags.
+                        0);
+
+  input.mSimulateMomentum =
+      Preferences::GetBool("apz.test.headless.simulate_momentum");
+
+  DispatchPanGestureInput(input);
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla