Coalesce async touch move events until the ack back from render

content/common/input/web_input_event_traits.cc

Index: content/common/input/web_input_event_traits.cc
diff --git a/content/common/input/web_input_event_traits.cc b/content/common/input/web_input_event_traits.cc
index 6ca962b5720d9741d2b6bc4d4d251f7e9a86b9ec..337a3620e67d6f42cc51b7e898ffee9e92f58a05 100644
--- a/content/common/input/web_input_event_traits.cc
+++ b/content/common/input/web_input_event_traits.cc
@@ -461,6 +461,8 @@ void WebInputEventTraits::Coalesce(const WebInputEvent& event_to_coalesce,
   Apply(WebInputEventCoalesce(), event->type, event_to_coalesce, event);
 }
 
+// For touchmove events, we always need an ACK back from render, and for async
+// touch move, we will also send a fake ACK.

[tdresser, 2015/03/25 14:16:18]

I'd move this comment down to where we deal with TouchStart and TouchEnd events.

[lanwei, 2015/03/26 11:54:38]

Done.

 bool WebInputEventTraits::IgnoresAckDisposition(const WebInputEvent& event) {
   switch (event.type) {
     case WebInputEvent::MouseDown:
@@ -479,7 +481,6 @@ bool WebInputEventTraits::IgnoresAckDisposition(const WebInputEvent& event) {
     case WebInputEvent::TouchCancel:
       return true;
     case WebInputEvent::TouchStart:
-    case WebInputEvent::TouchMove:
     case WebInputEvent::TouchEnd:
       return !static_cast<const WebTouchEvent&>(event).cancelable;
     default: