Modify gesture event types for WebView-tag scroll bubbling.

Source/platform/PlatformWheelEvent.h

Index: Source/platform/PlatformWheelEvent.h
diff --git a/Source/platform/PlatformWheelEvent.h b/Source/platform/PlatformWheelEvent.h
index cb23eff66496b97924249da99a91ab15ef7da28c..51c363873c733e1604a481453090d4ae5de7138d 100644
--- a/Source/platform/PlatformWheelEvent.h
+++ b/Source/platform/PlatformWheelEvent.h
@@ -64,6 +64,7 @@ public:
         , m_granularity(ScrollByPixelWheelEvent)
         , m_hasPreciseScrollingDeltas(false)
         , m_canScroll(true)
+        , m_resendSource(0)
         , m_railsMode(RailsModeFree)
 #if OS(MACOSX)
         , m_phase(PlatformWheelEventPhaseNone)
@@ -74,7 +75,7 @@ public:
     {
     }
 
-    PlatformWheelEvent(IntPoint position, IntPoint globalPosition, float deltaX, float deltaY, float wheelTicksX, float wheelTicksY, PlatformWheelEventGranularity granularity, bool shiftKey, bool ctrlKey, bool altKey, bool metaKey)
+    PlatformWheelEvent(IntPoint position, IntPoint globalPosition, float deltaX, float deltaY, float wheelTicksX, float wheelTicksY, PlatformWheelEventGranularity granularity, int resendSource, bool shiftKey, bool ctrlKey, bool altKey, bool metaKey)
         : PlatformEvent(PlatformEvent::Wheel, shiftKey, ctrlKey, altKey, metaKey, 0)
         , m_position(position)
         , m_globalPosition(globalPosition)
@@ -85,6 +86,7 @@ public:
         , m_granularity(granularity)
         , m_hasPreciseScrollingDeltas(false)
         , m_canScroll(true)
+        , m_resendSource(resendSource)
         , m_railsMode(RailsModeFree)
 #if OS(MACOSX)
         , m_phase(PlatformWheelEventPhaseNone)
@@ -110,6 +112,7 @@ public:
     void setHasPreciseScrollingDeltas(bool b) { m_hasPreciseScrollingDeltas = b; }
     bool canScroll() const { return m_canScroll; }
     void setCanScroll(bool b) { m_canScroll = b; }
+    int resendSource() const { return m_resendSource; }
     RailsMode railsMode() const { return m_railsMode; }
 
 #if OS(MACOSX)
@@ -129,6 +132,7 @@ protected:
     PlatformWheelEventGranularity m_granularity;
     bool m_hasPreciseScrollingDeltas;
     bool m_canScroll;
+    int m_resendSource;
     RailsMode m_railsMode;
 #if OS(MACOSX)
     PlatformWheelEventPhase m_phase;