From 537e832f5ac7345d9d2ee29c09c27b31867f21a2 Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@mozilla.com>
Date: Mon, 15 Dec 2014 23:31:12 -0800
Subject: [PATCH] Forward Windows events to APZ directly from nsWindow. (bug
 1109985 part 2, r=kats)

---
 dom/ipc/TabParent.cpp             | 15 +++++++++++++++
 gfx/layers/apz/src/InputQueue.cpp |  6 +++---
 widget/windows/nsWindow.cpp       | 13 +++++++++++++
 3 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index 919230f1a9e1..e0dcb057a7a3 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -19,6 +19,7 @@
 #include "mozilla/Hal.h"
 #include "mozilla/ipc/DocumentRendererParent.h"
 #include "mozilla/layers/CompositorParent.h"
+#include "mozilla/layers/InputAPZContext.h"
 #include "mozilla/layout/RenderFrameParent.h"
 #include "mozilla/MouseEvents.h"
 #include "mozilla/net/NeckoChild.h"
@@ -2103,6 +2104,20 @@ TabParent::MaybeForwardEventToRenderFrame(WidgetInputEvent& aEvent,
                                           ScrollableLayerGuid* aOutTargetGuid,
                                           uint64_t* aOutInputBlockId)
 {
+  if (aEvent.mClass == eWheelEventClass) {
+    // Wheel events must be sent to APZ directly from the widget. New APZ-
+    // aware events should follow suit and move there as well. However, we
+    // do need to inform the child process of the correct target and block
+    // id.
+    if (aOutTargetGuid) {
+      *aOutTargetGuid = InputAPZContext::GetTargetLayerGuid();
+    }
+    if (aOutInputBlockId) {
+      *aOutInputBlockId = InputAPZContext::GetInputBlockId();
+    }
+    return nsEventStatus_eIgnore;
+  }
+
   if (RenderFrameParent* rfp = GetRenderFrame()) {
     return rfp->NotifyInputEvent(aEvent, aOutTargetGuid, aOutInputBlockId);
   }
diff --git a/gfx/layers/apz/src/InputQueue.cpp b/gfx/layers/apz/src/InputQueue.cpp
index 3cc424aafe19..51275ab69be2 100644
--- a/gfx/layers/apz/src/InputQueue.cpp
+++ b/gfx/layers/apz/src/InputQueue.cpp
@@ -55,8 +55,8 @@ InputQueue::ReceiveInputEvent(const nsRefPtr<AsyncPanZoomController>& aTarget,
 
 bool
 InputQueue::MaybeHandleCurrentBlock(const nsRefPtr<AsyncPanZoomController>& aTarget,
-                                           CancelableBlockState *block,
-                                           const InputData& aEvent) {
+                                    CancelableBlockState *block,
+                                    const InputData& aEvent) {
   if (block == CurrentBlock() && block->IsReadyForHandling()) {
     INPQ_LOG("current block is ready with target %p preventdefault %d\n",
         aTarget.get(), block->IsDefaultPrevented());
@@ -162,7 +162,7 @@ InputQueue::ReceiveScrollWheelInput(const nsRefPtr<AsyncPanZoomController>& aTar
     block->AddEvent(aEvent.AsScrollWheelInput());
   }
 
-  return nsEventStatus_eIgnore;
+  return nsEventStatus_eConsumeDoDefault;
 }
 
 void
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index d0b9820f8217..1d56e9533f77 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -187,6 +187,7 @@
 #endif
 
 #include "mozilla/layers/APZCTreeManager.h"
+#include "mozilla/layers/InputAPZContext.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -3741,6 +3742,18 @@ bool nsWindow::DispatchKeyboardEvent(WidgetGUIEvent* event)
 
 bool nsWindow::DispatchScrollEvent(WidgetGUIEvent* aEvent)
 {
+  uint64_t inputBlockId = 0;
+  ScrollableLayerGuid guid;
+
+  if (mAPZC && aEvent->mClass == eWheelEventClass) {
+    nsEventStatus status = mAPZC->ReceiveInputEvent(*aEvent->AsWheelEvent(), &guid, &inputBlockId);
+    if (status == nsEventStatus_eConsumeNoDefault) {
+      return true;
+    }
+  }
+
+  InputAPZContext context(guid, inputBlockId);
+
   nsEventStatus status;
   DispatchEvent(aEvent, status);
   return ConvertStatus(status);