1 files changed, 553 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/APZEventState.cpp b/gfx/layers/apz/util/APZEventState.cpp
new file mode 100644
index 0000000000..159952f772
--- /dev/null
+++ b/gfx/layers/apz/util/APZEventState.cpp
@@ -0,0 +1,553 @@
+/* -*- 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/. */
+
+#include "APZEventState.h"
+
+#include <utility>
+
+#include "APZCCallbackHelper.h"
+#include "ActiveElementManager.h"
+#include "TouchManager.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/PositionedEventTargeting.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/ToString.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/ViewportUtils.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/widget/nsAutoRollup.h"
+#include "nsCOMPtr.h"
+#include "nsDocShell.h"
+#include "nsIDOMWindowUtils.h"
+#include "nsINamed.h"
+#include "nsIScrollableFrame.h"
+#include "nsIScrollbarMediator.h"
+#include "nsITimer.h"
+#include "nsIWeakReferenceUtils.h"
+#include "nsIWidget.h"
+#include "nsLayoutUtils.h"
+#include "nsQueryFrame.h"
+
+static mozilla::LazyLogModule sApzEvtLog("apz.eventstate");
+#define APZES_LOG(...) MOZ_LOG(sApzEvtLog, LogLevel::Debug, (__VA_ARGS__))
+
+// Static helper functions
+namespace {
+
+int32_t WidgetModifiersToDOMModifiers(mozilla::Modifiers aModifiers) {
+  int32_t result = 0;
+  if (aModifiers & mozilla::MODIFIER_SHIFT) {
+    result |= nsIDOMWindowUtils::MODIFIER_SHIFT;
+  }
+  if (aModifiers & mozilla::MODIFIER_CONTROL) {
+    result |= nsIDOMWindowUtils::MODIFIER_CONTROL;
+  }
+  if (aModifiers & mozilla::MODIFIER_ALT) {
+    result |= nsIDOMWindowUtils::MODIFIER_ALT;
+  }
+  if (aModifiers & mozilla::MODIFIER_META) {
+    result |= nsIDOMWindowUtils::MODIFIER_META;
+  }
+  if (aModifiers & mozilla::MODIFIER_ALTGRAPH) {
+    result |= nsIDOMWindowUtils::MODIFIER_ALTGRAPH;
+  }
+  if (aModifiers & mozilla::MODIFIER_CAPSLOCK) {
+    result |= nsIDOMWindowUtils::MODIFIER_CAPSLOCK;
+  }
+  if (aModifiers & mozilla::MODIFIER_FN) {
+    result |= nsIDOMWindowUtils::MODIFIER_FN;
+  }
+  if (aModifiers & mozilla::MODIFIER_FNLOCK) {
+    result |= nsIDOMWindowUtils::MODIFIER_FNLOCK;
+  }
+  if (aModifiers & mozilla::MODIFIER_NUMLOCK) {
+    result |= nsIDOMWindowUtils::MODIFIER_NUMLOCK;
+  }
+  if (aModifiers & mozilla::MODIFIER_SCROLLLOCK) {
+    result |= nsIDOMWindowUtils::MODIFIER_SCROLLLOCK;
+  }
+  if (aModifiers & mozilla::MODIFIER_SYMBOL) {
+    result |= nsIDOMWindowUtils::MODIFIER_SYMBOL;
+  }
+  if (aModifiers & mozilla::MODIFIER_SYMBOLLOCK) {
+    result |= nsIDOMWindowUtils::MODIFIER_SYMBOLLOCK;
+  }
+  if (aModifiers & mozilla::MODIFIER_OS) {
+    result |= nsIDOMWindowUtils::MODIFIER_OS;
+  }
+  return result;
+}
+
+}  // namespace
+
+namespace mozilla {
+namespace layers {
+
+APZEventState::APZEventState(nsIWidget* aWidget,
+                             ContentReceivedInputBlockCallback&& aCallback)
+    : mWidget(nullptr)  // initialized in constructor body
+      ,
+      mActiveElementManager(new ActiveElementManager()),
+      mContentReceivedInputBlockCallback(std::move(aCallback)),
+      mPendingTouchPreventedResponse(false),
+      mPendingTouchPreventedBlockId(0),
+      mEndTouchIsClick(false),
+      mFirstTouchCancelled(false),
+      mTouchEndCancelled(false),
+      mLastTouchIdentifier(0) {
+  nsresult rv;
+  mWidget = do_GetWeakReference(aWidget, &rv);
+  MOZ_ASSERT(NS_SUCCEEDED(rv),
+             "APZEventState constructed with a widget that"
+             " does not support weak references. APZ will NOT work!");
+}
+
+APZEventState::~APZEventState() = default;
+
+class DelayedFireSingleTapEvent final : public nsITimerCallback,
+                                        public nsINamed {
+ public:
+  NS_DECL_ISUPPORTS
+
+  DelayedFireSingleTapEvent(nsWeakPtr aWidget, LayoutDevicePoint& aPoint,
+                            Modifiers aModifiers, int32_t aClickCount,
+                            nsITimer* aTimer, RefPtr<nsIContent>& aTouchRollup)
+      : mWidget(aWidget),
+        mPoint(aPoint),
+        mModifiers(aModifiers),
+        mClickCount(aClickCount)
+        // Hold the reference count until we are called back.
+        ,
+        mTimer(aTimer),
+        mTouchRollup(aTouchRollup) {}
+
+  NS_IMETHOD Notify(nsITimer*) override {
+    if (nsCOMPtr<nsIWidget> widget = do_QueryReferent(mWidget)) {
+      widget::nsAutoRollup rollup(mTouchRollup.get());
+      APZCCallbackHelper::FireSingleTapEvent(mPoint, mModifiers, mClickCount,
+                                             widget);
+    }
+    mTimer = nullptr;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetName(nsACString& aName) override {
+    aName.AssignLiteral("DelayedFireSingleTapEvent");
+    return NS_OK;
+  }
+
+  void ClearTimer() { mTimer = nullptr; }
+
+ private:
+  ~DelayedFireSingleTapEvent() = default;
+
+  nsWeakPtr mWidget;
+  LayoutDevicePoint mPoint;
+  Modifiers mModifiers;
+  int32_t mClickCount;
+  nsCOMPtr<nsITimer> mTimer;
+  RefPtr<nsIContent> mTouchRollup;
+};
+
+NS_IMPL_ISUPPORTS(DelayedFireSingleTapEvent, nsITimerCallback, nsINamed)
+
+void APZEventState::ProcessSingleTap(const CSSPoint& aPoint,
+                                     const CSSToLayoutDeviceScale& aScale,
+                                     Modifiers aModifiers,
+                                     int32_t aClickCount) {
+  APZES_LOG("Handling single tap at %s with %d\n", ToString(aPoint).c_str(),
+            mTouchEndCancelled);
+
+  RefPtr<nsIContent> touchRollup = GetTouchRollup();
+  mTouchRollup = nullptr;
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  if (!widget) {
+    return;
+  }
+
+  if (mTouchEndCancelled) {
+    return;
+  }
+
+  LayoutDevicePoint ldPoint = aPoint * aScale;
+
+  APZES_LOG("Scheduling timer for click event\n");
+  nsCOMPtr<nsITimer> timer = NS_NewTimer();
+  RefPtr<DelayedFireSingleTapEvent> callback = new DelayedFireSingleTapEvent(
+      mWidget, ldPoint, aModifiers, aClickCount, timer, touchRollup);
+  nsresult rv = timer->InitWithCallback(
+      callback, StaticPrefs::ui_touch_activation_duration_ms(),
+      nsITimer::TYPE_ONE_SHOT);
+  if (NS_FAILED(rv)) {
+    // Make |callback| not hold the timer, so they will both be destructed when
+    // we leave the scope of this function.
+    callback->ClearTimer();
+  }
+}
+
+bool APZEventState::FireContextmenuEvents(PresShell* aPresShell,
+                                          const CSSPoint& aPoint,
+                                          const CSSToLayoutDeviceScale& aScale,
+                                          Modifiers aModifiers,
+                                          const nsCOMPtr<nsIWidget>& aWidget) {
+  // Suppress retargeting for mouse events generated by a long-press
+  EventRetargetSuppression suppression;
+
+  // Synthesize mousemove event for allowing users to emulate to move mouse
+  // cursor over the element.  As a result, users can open submenu UI which
+  // is opened when mouse cursor is moved over a link (i.e., it's a case that
+  // users cannot stay in the page after tapping it).  So, this improves
+  // accessibility in websites which are designed for desktop.
+  // Note that we don't need to check whether mousemove event is consumed or
+  // not because Chrome also ignores the result.
+  APZCCallbackHelper::DispatchSynthesizedMouseEvent(
+      eMouseMove, 0 /* time */, aPoint * aScale, aModifiers, 0 /* clickCount */,
+      aWidget);
+
+  // Converting the modifiers to DOM format for the DispatchMouseEvent call
+  // is the most useless thing ever because nsDOMWindowUtils::SendMouseEvent
+  // just converts them back to widget format, but that API has many callers,
+  // including in JS code, so it's not trivial to change.
+  CSSPoint point = CSSPoint::FromAppUnits(
+      ViewportUtils::VisualToLayout(CSSPoint::ToAppUnits(aPoint), aPresShell));
+  bool eventHandled = APZCCallbackHelper::DispatchMouseEvent(
+      aPresShell, u"contextmenu"_ns, point, 2, 1,
+      WidgetModifiersToDOMModifiers(aModifiers),
+      dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH,
+      0 /* Use the default value here. */);
+
+  APZES_LOG("Contextmenu event handled: %d\n", eventHandled);
+  if (eventHandled) {
+    // If the contextmenu event was handled then we're showing a contextmenu,
+    // and so we should remove any activation
+    mActiveElementManager->ClearActivation();
+#ifndef XP_WIN
+  } else {
+    // If the contextmenu wasn't consumed, fire the eMouseLongTap event.
+    nsEventStatus status = APZCCallbackHelper::DispatchSynthesizedMouseEvent(
+        eMouseLongTap, /*time*/ 0, aPoint * aScale, aModifiers,
+        /*clickCount*/ 1, aWidget);
+    eventHandled = (status == nsEventStatus_eConsumeNoDefault);
+    APZES_LOG("eMouseLongTap event handled: %d\n", eventHandled);
+#endif
+  }
+
+  return eventHandled;
+}
+
+void APZEventState::ProcessLongTap(PresShell* aPresShell,
+                                   const CSSPoint& aPoint,
+                                   const CSSToLayoutDeviceScale& aScale,
+                                   Modifiers aModifiers,
+                                   uint64_t aInputBlockId) {
+  APZES_LOG("Handling long tap at %s\n", ToString(aPoint).c_str());
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  if (!widget) {
+    return;
+  }
+
+  SendPendingTouchPreventedResponse(false);
+
+#ifdef XP_WIN
+  // On Windows, we fire the contextmenu events when the user lifts their
+  // finger, in keeping with the platform convention. This happens in the
+  // ProcessLongTapUp function. However, we still fire the eMouseLongTap event
+  // at this time, because things like text selection or dragging may want
+  // to know about it.
+  nsEventStatus status = APZCCallbackHelper::DispatchSynthesizedMouseEvent(
+      eMouseLongTap, /*time*/ 0, aPoint * aScale, aModifiers, /*clickCount*/ 1,
+      widget);
+
+  bool eventHandled = (status == nsEventStatus_eConsumeNoDefault);
+#else
+  bool eventHandled =
+      FireContextmenuEvents(aPresShell, aPoint, aScale, aModifiers, widget);
+#endif
+  mContentReceivedInputBlockCallback(aInputBlockId, eventHandled);
+
+  if (eventHandled) {
+    // Also send a touchcancel to content, so that listeners that might be
+    // waiting for a touchend don't trigger.
+    WidgetTouchEvent cancelTouchEvent(true, eTouchCancel, widget.get());
+    cancelTouchEvent.mModifiers = aModifiers;
+    auto ldPoint = LayoutDeviceIntPoint::Round(aPoint * aScale);
+    cancelTouchEvent.mTouches.AppendElement(new mozilla::dom::Touch(
+        mLastTouchIdentifier, ldPoint, LayoutDeviceIntPoint(), 0, 0));
+    APZCCallbackHelper::DispatchWidgetEvent(cancelTouchEvent);
+  }
+}
+
+void APZEventState::ProcessLongTapUp(PresShell* aPresShell,
+                                     const CSSPoint& aPoint,
+                                     const CSSToLayoutDeviceScale& aScale,
+                                     Modifiers aModifiers) {
+#ifdef XP_WIN
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  if (widget) {
+    FireContextmenuEvents(aPresShell, aPoint, aScale, aModifiers, widget);
+  }
+#endif
+}
+
+void APZEventState::ProcessTouchEvent(
+    const WidgetTouchEvent& aEvent, const ScrollableLayerGuid& aGuid,
+    uint64_t aInputBlockId, nsEventStatus aApzResponse,
+    nsEventStatus aContentResponse,
+    nsTArray<TouchBehaviorFlags>&& aAllowedTouchBehaviors) {
+  if (aEvent.mMessage == eTouchStart && aEvent.mTouches.Length() > 0) {
+    mActiveElementManager->SetTargetElement(aEvent.mTouches[0]->GetTarget());
+    mLastTouchIdentifier = aEvent.mTouches[0]->Identifier();
+  }
+  if (aEvent.mMessage == eTouchStart) {
+    // We get the allowed touch behaviors on a touchstart, but may not actually
+    // use them until the first touchmove, so we stash them in a member
+    // variable.
+    mTouchBlockAllowedBehaviors = std::move(aAllowedTouchBehaviors);
+  }
+
+  bool isTouchPrevented = aContentResponse == nsEventStatus_eConsumeNoDefault;
+  bool sentContentResponse = false;
+  APZES_LOG("Handling event type %d isPrevented=%d\n", aEvent.mMessage,
+            isTouchPrevented);
+  switch (aEvent.mMessage) {
+    case eTouchStart: {
+      mTouchEndCancelled = false;
+      mTouchRollup = do_GetWeakReference(widget::nsAutoRollup::GetLastRollup());
+
+      SendPendingTouchPreventedResponse(false);
+      // The above call may have sent a message to APZ if we get two
+      // TOUCH_STARTs in a row and just responded to the first one.
+
+      // We're about to send a response back to APZ, but we should only do it
+      // for events that went through APZ (which should be all of them).
+      MOZ_ASSERT(aEvent.mFlags.mHandledByAPZ);
+
+      // If the first touchstart event was preventDefaulted, ensure that any
+      // subsequent additional touchstart events also get preventDefaulted. This
+      // ensures that e.g. pinch zooming is prevented even if just the first
+      // touchstart was prevented by content.
+      if (mTouchCounter.GetActiveTouchCount() == 0) {
+        mFirstTouchCancelled = isTouchPrevented;
+      } else {
+        if (mFirstTouchCancelled && !isTouchPrevented) {
+          APZES_LOG(
+              "Propagating prevent-default from first-touch for block %" PRIu64
+              "\n",
+              aInputBlockId);
+        }
+        isTouchPrevented |= mFirstTouchCancelled;
+      }
+
+      if (isTouchPrevented) {
+        mContentReceivedInputBlockCallback(aInputBlockId, isTouchPrevented);
+        sentContentResponse = true;
+      } else {
+        APZES_LOG("Event not prevented; pending response for %" PRIu64 " %s\n",
+                  aInputBlockId, ToString(aGuid).c_str());
+        mPendingTouchPreventedResponse = true;
+        mPendingTouchPreventedGuid = aGuid;
+        mPendingTouchPreventedBlockId = aInputBlockId;
+      }
+      break;
+    }
+
+    case eTouchEnd:
+      if (isTouchPrevented) {
+        mTouchEndCancelled = true;
+        mEndTouchIsClick = false;
+      }
+      [[fallthrough]];
+    case eTouchCancel:
+      mActiveElementManager->HandleTouchEndEvent(mEndTouchIsClick);
+      [[fallthrough]];
+    case eTouchMove: {
+      if (mPendingTouchPreventedResponse) {
+        MOZ_ASSERT(aGuid == mPendingTouchPreventedGuid);
+      }
+      sentContentResponse = SendPendingTouchPreventedResponse(isTouchPrevented);
+      break;
+    }
+
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unknown touch event type");
+      break;
+  }
+
+  mTouchCounter.Update(aEvent);
+  if (mTouchCounter.GetActiveTouchCount() == 0) {
+    mFirstTouchCancelled = false;
+  }
+
+  APZES_LOG("Pointercancel if %d %d %d %d %d\n", sentContentResponse,
+            !isTouchPrevented, aApzResponse == nsEventStatus_eConsumeDoDefault,
+            StaticPrefs::dom_w3c_pointer_events_enabled(),
+            MainThreadAgreesEventsAreConsumableByAPZ());
+  if (sentContentResponse && !isTouchPrevented &&
+      aApzResponse == nsEventStatus_eConsumeDoDefault &&
+      StaticPrefs::dom_w3c_pointer_events_enabled() &&
+      MainThreadAgreesEventsAreConsumableByAPZ()) {
+    WidgetTouchEvent cancelEvent(aEvent);
+    cancelEvent.mMessage = eTouchPointerCancel;
+    cancelEvent.mFlags.mCancelable = false;  // mMessage != eTouchCancel;
+    for (uint32_t i = 0; i < cancelEvent.mTouches.Length(); ++i) {
+      if (mozilla::dom::Touch* touch = cancelEvent.mTouches[i]) {
+        touch->convertToPointer = true;
+      }
+    }
+    nsEventStatus status;
+    cancelEvent.mWidget->DispatchEvent(&cancelEvent, status);
+  }
+}
+
+bool APZEventState::MainThreadAgreesEventsAreConsumableByAPZ() const {
+  // APZ errs on the side of saying it can consume touch events to perform
+  // default user-agent behaviours. In particular it may say this if it hasn't
+  // received accurate touch-action information. Here we double-check using
+  // accurate touch-action information. This code is kinda-sorta the main
+  // thread equivalent of AsyncPanZoomController::ArePointerEventsConsumable().
+
+  switch (mTouchBlockAllowedBehaviors.Length()) {
+    case 0:
+      // If we don't have any touch-action (e.g. because it is disabled) then
+      // APZ has no restrictions.
+      return true;
+
+    case 1: {
+      // If there's one touch point in this touch block, then check the pan-x
+      // and pan-y flags. If neither is allowed, then we disagree with APZ and
+      // say that it can't do anything with this touch block. Note that it would
+      // be even better if we could check the allowed scroll directions of the
+      // scrollframe at this point and refine this further.
+      TouchBehaviorFlags flags = mTouchBlockAllowedBehaviors[0];
+      return (flags & AllowedTouchBehavior::HORIZONTAL_PAN) ||
+             (flags & AllowedTouchBehavior::VERTICAL_PAN);
+    }
+
+    case 2: {
+      // If there's two touch points in this touch block, check that they both
+      // allow zooming.
+      for (const auto& allowed : mTouchBlockAllowedBehaviors) {
+        if (!(allowed & AllowedTouchBehavior::PINCH_ZOOM)) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    default:
+      // More than two touch points? APZ shouldn't be doing anything with this,
+      // so APZ shouldn't be consuming them.
+      return false;
+  }
+}
+
+void APZEventState::ProcessWheelEvent(const WidgetWheelEvent& aEvent,
+                                      uint64_t aInputBlockId) {
+  // If this event starts a swipe, indicate that it shouldn't result in a
+  // scroll by setting defaultPrevented to true.
+  bool defaultPrevented = aEvent.DefaultPrevented() || aEvent.TriggersSwipe();
+  mContentReceivedInputBlockCallback(aInputBlockId, defaultPrevented);
+}
+
+void APZEventState::ProcessMouseEvent(const WidgetMouseEvent& aEvent,
+                                      uint64_t aInputBlockId) {
+  bool defaultPrevented = false;
+  mContentReceivedInputBlockCallback(aInputBlockId, defaultPrevented);
+}
+
+void APZEventState::ProcessAPZStateChange(ViewID aViewId,
+                                          APZStateChange aChange, int aArg) {
+  switch (aChange) {
+    case APZStateChange::eTransformBegin: {
+      nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aViewId);
+      if (sf) {
+        sf->SetTransformingByAPZ(true);
+      }
+      nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(sf);
+      if (scrollbarMediator) {
+        scrollbarMediator->ScrollbarActivityStarted();
+      }
+
+      nsIContent* content = nsLayoutUtils::FindContentFor(aViewId);
+      dom::Document* doc = content ? content->GetComposedDoc() : nullptr;
+      nsCOMPtr<nsIDocShell> docshell(doc ? doc->GetDocShell() : nullptr);
+      if (docshell && sf) {
+        nsDocShell* nsdocshell = static_cast<nsDocShell*>(docshell.get());
+        nsdocshell->NotifyAsyncPanZoomStarted();
+      }
+      break;
+    }
+    case APZStateChange::eTransformEnd: {
+      nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aViewId);
+      if (sf) {
+        sf->SetTransformingByAPZ(false);
+      }
+      nsIScrollbarMediator* scrollbarMediator = do_QueryFrame(sf);
+      if (scrollbarMediator) {
+        scrollbarMediator->ScrollbarActivityStopped();
+      }
+
+      nsIContent* content = nsLayoutUtils::FindContentFor(aViewId);
+      dom::Document* doc = content ? content->GetComposedDoc() : nullptr;
+      nsCOMPtr<nsIDocShell> docshell(doc ? doc->GetDocShell() : nullptr);
+      if (docshell && sf) {
+        nsDocShell* nsdocshell = static_cast<nsDocShell*>(docshell.get());
+        nsdocshell->NotifyAsyncPanZoomStopped();
+      }
+      break;
+    }
+    case APZStateChange::eStartTouch: {
+      mActiveElementManager->HandleTouchStart(aArg);
+      break;
+    }
+    case APZStateChange::eStartPanning: {
+      // The user started to pan, so we don't want anything to be :active.
+      mActiveElementManager->ClearActivation();
+      break;
+    }
+    case APZStateChange::eEndTouch: {
+      mEndTouchIsClick = aArg;
+      mActiveElementManager->HandleTouchEnd();
+      break;
+    }
+  }
+}
+
+bool APZEventState::SendPendingTouchPreventedResponse(bool aPreventDefault) {
+  if (mPendingTouchPreventedResponse) {
+    APZES_LOG("Sending response %d for pending guid: %s\n", aPreventDefault,
+              ToString(mPendingTouchPreventedGuid).c_str());
+    mContentReceivedInputBlockCallback(mPendingTouchPreventedBlockId,
+                                       aPreventDefault);
+    mPendingTouchPreventedResponse = false;
+    return true;
+  }
+  return false;
+}
+
+already_AddRefed<nsIWidget> APZEventState::GetWidget() const {
+  nsCOMPtr<nsIWidget> result = do_QueryReferent(mWidget);
+  return result.forget();
+}
+
+already_AddRefed<nsIContent> APZEventState::GetTouchRollup() const {
+  nsCOMPtr<nsIContent> result = do_QueryReferent(mTouchRollup);
+  return result.forget();
+}
+
+}  // namespace layers
+}  // namespace mozilla