Modify gesture event types for WebView-tag scroll bubbling.

Source/platform/PlatformGestureEvent.h

 /*
  * Copyright (C) 2011 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
         bool shiftKey, bool ctrlKey, bool altKey, bool metaKey)
         : PlatformEvent(type, shiftKey, ctrlKey, altKey, metaKey, timestamp)
         , m_position(position)
         , m_globalPosition(globalPosition)
         , m_area(area)
     {
         memset(&m_data, 0, sizeof(m_data));
     }
 
     void setScrollGestureData(float deltaX, float deltaY, float velocityX, float velocityY,
-        bool inertial, bool preventPropagation)
+        bool inertial, int resendSource, bool preventPropagation)
     {
         ASSERT(type() == PlatformEvent::GestureScrollBegin
             || type() == PlatformEvent::GestureScrollUpdate
             || type() == PlatformEvent::GestureScrollEnd);
         if (type() != GestureScrollUpdate) {
             ASSERT(deltaX == 0);
             ASSERT(deltaY == 0);
             ASSERT(velocityX == 0);
             ASSERT(velocityY == 0);
             ASSERT(!preventPropagation);
         }
 
         if (type() == PlatformEvent::GestureScrollBegin)
             ASSERT(!inertial);
 
         m_data.m_scroll.m_deltaX = deltaX;
         m_data.m_scroll.m_deltaY = deltaY;
         m_data.m_scroll.m_velocityX = velocityX;
         m_data.m_scroll.m_velocityY = velocityY;
         m_data.m_scroll.m_inertial = inertial;
+        m_data.m_scroll.m_resendSource = resendSource;
         m_data.m_scroll.m_preventPropagation = preventPropagation;
     }
 
     const IntPoint& position() const { return m_position; } // PlatformWindow coordinates.
     const IntPoint& globalPosition() const { return m_globalPosition; } // Screen coordinates.
 
     const IntSize& area() const { return m_area; }
 
     float deltaX() const
     {
         ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
         return m_data.m_scroll.m_deltaX;
     }
 
     float deltaY() const
     {
         ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
         return m_data.m_scroll.m_deltaY;
     }
 
     int tapCount() const
     {
         ASSERT(m_type == PlatformEvent::GestureTap);
         return m_data.m_tap.m_tapCount;
     }
 
     float velocityX() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
+        ASSERT(m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureFlingStart);
         return m_data.m_scroll.m_velocityX;
     }
 
     float velocityY() const
     {
-        ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
+        ASSERT(m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureFlingStart);
         return m_data.m_scroll.m_velocityY;
     }
 
     bool inertial() const
     {
         ASSERT(m_type == PlatformEvent::GestureScrollUpdate || m_type == PlatformEvent::GestureScrollEnd);
         return m_data.m_scroll.m_inertial;
     }
 
+    int resendSource() const
+    {

[tdresser, 2015/09/11 15:25:20]

Can we keep this consistent with the other accessors, which assert that the type
is correct?

[wjmaclean, 2015/09/11 15:31:01]

Sure, I'll add an ASSERT in the next version of the patch.

+        if (isScrollEvent())
+            return m_data.m_scroll.m_resendSource;
+
+        return 0;
+    }
+
     bool preventPropagation() const
     {
         ASSERT(m_type == PlatformEvent::GestureScrollUpdate);
         return m_data.m_scroll.m_preventPropagation;
     }
 
     float scale() const
     {
         ASSERT(m_type == PlatformEvent::GesturePinchUpdate);
         return m_data.m_pinchUpdate.m_scale;
@@ skipping 45 matching lines @@
             int m_tapCount;
         } m_tap;
 
         struct {
             float m_deltaX;
             float m_deltaY;
             float m_velocityX;
             float m_velocityY;
             int m_preventPropagation;
             bool m_inertial;
+            int m_resendSource;

[tdresser, 2015/09/11 15:25:20]

Why is this an int?

[wjmaclean, 2015/09/11 15:31:01]

Since there can be multiple BrowserPlugins in a page, the guest will put the
BrowserPlugin's unique ID into the resendSource field, just to check that it
makes it's way back to the right place in the embedder.

[tdresser, 2015/09/11 15:34:10]

Makes sense. Can we clarify the meaning with a better member name (or at least a
comment?).

Maybe something like resendingPluginId?

         } m_scroll;
 
         struct {
             float m_scale;
         } m_pinchUpdate;
     } m_data;
 };
 
 } // namespace blink
 
 #endif // PlatformGestureEvent_h