Handle in-process APZ events correctly on Windows. (bug 1111873 part 2, r=kats)

--HG--
extra : rebase_source : 8ca5156392705e3a1806fc6a15154dbaa380f438

dom/ipc/TabParent.cpp

@@ -2150,6 +2150,11 @@ TabParent::MaybeForwardEventToRenderFrame(WidgetInputEvent& aEvent,
     if (aOutInputBlockId) {
       *aOutInputBlockId = InputAPZContext::GetInputBlockId();
     }
+
+    // Let the widget know that the event will be sent to the child process,
+    // which will (hopefully) send a confirmation notice back to APZ.
+    InputAPZContext::SetRoutedToChildProcess();
+
     return nsEventStatus_eIgnore;
   }
 

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -1013,6 +1013,13 @@ APZCTreeManager::SetTargetAPZC(uint64_t aInputBlockId,
   mInputQueue->SetConfirmedTargetApzc(aInputBlockId, target);
 }
 
+void
+APZCTreeManager::SetTargetAPZC(uint64_t aInputBlockId, const ScrollableLayerGuid& aTarget)
+{
+  nsRefPtr<AsyncPanZoomController> target = GetTargetAPZC(aTarget);
+  mInputQueue->SetConfirmedTargetApzc(aInputBlockId, target);
+}
+
 void
 APZCTreeManager::UpdateZoomConstraints(const ScrollableLayerGuid& aGuid,
                                        const ZoomConstraints& aConstraints)

gfx/layers/apz/src/APZCTreeManager.h

@@ -228,6 +228,12 @@ public:
   void SetTargetAPZC(uint64_t aInputBlockId,
                      const nsTArray<ScrollableLayerGuid>& aTargets);
 
+  /**
+   * Helper function for SetTargetAPZC when used with single-target events,
+   * such as mouse wheel events.
+   */
+  void SetTargetAPZC(uint64_t aInputBlockId, const ScrollableLayerGuid& aTarget);
+
   /**
    * Updates any zoom constraints contained in the <meta name="viewport"> tag.
    */

gfx/layers/apz/util/InputAPZContext.cpp

@@ -10,6 +10,7 @@ namespace layers {
 
 ScrollableLayerGuid InputAPZContext::sGuid;
 uint64_t InputAPZContext::sBlockId = 0;
+bool InputAPZContext::sRoutedToChildProcess = false;
 
 /*static*/ ScrollableLayerGuid
 InputAPZContext::GetTargetLayerGuid()
@@ -23,19 +24,34 @@ InputAPZContext::GetInputBlockId()
   return sBlockId;
 }
 
+/*static*/ void
+InputAPZContext::SetRoutedToChildProcess()
+{
+  sRoutedToChildProcess = true;
+}
+
 InputAPZContext::InputAPZContext(const ScrollableLayerGuid& aGuid,
                                  const uint64_t& aBlockId)
   : mOldGuid(sGuid)
   , mOldBlockId(sBlockId)
+  , mOldRoutedToChildProcess(sRoutedToChildProcess)
 {
   sGuid = aGuid;
   sBlockId = aBlockId;
+  sRoutedToChildProcess = false;
 }
 
 InputAPZContext::~InputAPZContext()
 {
   sGuid = mOldGuid;
   sBlockId = mOldBlockId;
+  sRoutedToChildProcess = mOldRoutedToChildProcess;
+}
+
+bool
+InputAPZContext::WasRoutedToChildProcess()
+{
+  return sRoutedToChildProcess;
 }
 
 }

gfx/layers/apz/util/InputAPZContext.h

@@ -20,18 +20,23 @@ class MOZ_STACK_CLASS InputAPZContext
 private:
   static ScrollableLayerGuid sGuid;
   static uint64_t sBlockId;
+  static bool sRoutedToChildProcess;
 
 public:
   static ScrollableLayerGuid GetTargetLayerGuid();
   static uint64_t GetInputBlockId();
+  static void SetRoutedToChildProcess();
 
   InputAPZContext(const ScrollableLayerGuid& aGuid,
                     const uint64_t& aBlockId);
   ~InputAPZContext();
 
+  bool WasRoutedToChildProcess();
+
 private:
   ScrollableLayerGuid mOldGuid;
   uint64_t mOldBlockId;
+  bool mOldRoutedToChildProcess;
 };
 
 }

widget/nsBaseWidget.cpp

@@ -46,6 +46,8 @@
 #include "mozilla/VsyncDispatcher.h"
 #include "mozilla/layers/APZCTreeManager.h"
 #include "mozilla/layers/ChromeProcessController.h"
+#include "mozilla/layers/InputAPZContext.h"
+#include "mozilla/dom/TabParent.h"
 
 #ifdef ACCESSIBILITY
 #include "nsAccessibilityService.h"
@@ -940,6 +942,27 @@ void nsBaseWidget::ConfigureAPZCTreeManager()
   }
 }
 
+nsEventStatus
+nsBaseWidget::DispatchEventForAPZ(WidgetGUIEvent* aEvent,
+                                  const ScrollableLayerGuid& aGuid,
+                                  uint64_t aInputBlockId)
+{
+  InputAPZContext context(aGuid, aInputBlockId);
+
+  nsEventStatus status;
+  DispatchEvent(aEvent, status);
+
+  if (mAPZC && !context.WasRoutedToChildProcess()) {
+    // APZ did not find a dispatch-to-content region in the child process,
+    // and EventStateManager did not route the event into the child process.
+    // It's safe to communicate to APZ that the event has been processed.
+    mAPZC->SetTargetAPZC(aInputBlockId, aGuid);
+    mAPZC->ContentReceivedInputBlock(aInputBlockId, aEvent->mFlags.mDefaultPrevented);
+  }
+
+  return status;
+}
+
 void
 nsBaseWidget::GetPreferredCompositorBackends(nsTArray<LayersBackend>& aHints)
 {

widget/nsBaseWidget.h

@@ -36,6 +36,7 @@ class CompositorChild;
 class CompositorParent;
 class APZCTreeManager;
 class GeckoContentController;
+struct ScrollableLayerGuid;
 }
 
 class VsyncDispatcher;
@@ -88,6 +89,7 @@ protected:
   typedef mozilla::layers::CompositorParent CompositorParent;
   typedef mozilla::layers::APZCTreeManager APZCTreeManager;
   typedef mozilla::layers::GeckoContentController GeckoContentController;
+  typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
   typedef mozilla::ScreenRotation ScreenRotation;
 
   virtual ~nsBaseWidget();
@@ -311,6 +313,12 @@ protected:
   virtual void ConfigureAPZCTreeManager();
   virtual already_AddRefed<GeckoContentController> CreateRootContentController();
 
+  // Dispatch an event that has been routed through APZ directly from the
+  // widget.
+  nsEventStatus DispatchEventForAPZ(mozilla::WidgetGUIEvent* aEvent,
+                                    const ScrollableLayerGuid& aGuid,
+                                    uint64_t aInputBlockId);
+
   const nsIntRegion RegionFromArray(const nsTArray<nsIntRect>& aRects);
   void ArrayFromRegion(const nsIntRegion& aRegion, nsTArray<nsIntRect>& aRects);
 

widget/windows/nsWindow.cpp

@@ -3742,20 +3742,20 @@ bool nsWindow::DispatchKeyboardEvent(WidgetGUIEvent* event)
 
 bool nsWindow::DispatchScrollEvent(WidgetGUIEvent* aEvent)
 {
-  uint64_t inputBlockId = 0;
-  ScrollableLayerGuid guid;
+  nsEventStatus status;
 
   if (mAPZC && aEvent->mClass == eWheelEventClass) {
-    nsEventStatus status = mAPZC->ReceiveInputEvent(*aEvent->AsWheelEvent(), &guid, &inputBlockId);
-    if (status == nsEventStatus_eConsumeNoDefault) {
+    uint64_t inputBlockId = 0;
+    ScrollableLayerGuid guid;
+
+    nsEventStatus result = mAPZC->ReceiveInputEvent(*aEvent->AsWheelEvent(), &guid, &inputBlockId);
+    if (result == nsEventStatus_eConsumeNoDefault) {
       return true;
     }
+    status = DispatchEventForAPZ(aEvent, guid, inputBlockId);
+  } else {
+    DispatchEvent(aEvent, status);
   }
-
-  InputAPZContext context(guid, inputBlockId);
-
-  nsEventStatus status;
-  DispatchEvent(aEvent, status);
   return ConvertStatus(status);
 }