Coalesce async touch move events until the ack back from render

content/browser/renderer_host/input/input_router_impl.h

Index: content/browser/renderer_host/input/input_router_impl.h
diff --git a/content/browser/renderer_host/input/input_router_impl.h b/content/browser/renderer_host/input/input_router_impl.h
index 1abe33b6ad728fda3601ee28722f87e1874aa247..d002923e4892056369ef664fe16751d388958e6b 100644
--- a/content/browser/renderer_host/input/input_router_impl.h
+++ b/content/browser/renderer_host/input/input_router_impl.h
@@ -15,11 +15,10 @@
 #include "content/browser/renderer_host/input/touch_action_filter.h"
 #include "content/browser/renderer_host/input/touch_event_queue.h"
 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
+#include "content/common/input/input_event_ack.h"
 #include "content/common/input/input_event_stream_validator.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 
-struct InputHostMsg_HandleInputEvent_ACK_Params;
-
 namespace IPC {
 class Sender;
 }
@@ -124,7 +123,7 @@ private:
                        bool is_keyboard_shortcut);
 
   // IPC message handlers
-  void OnInputEventAck(const InputHostMsg_HandleInputEvent_ACK_Params& ack);
+  void OnInputEventAck(const InputEventAck& ack);
   void OnDidOverscroll(const DidOverscrollParams& params);
   void OnMsgMoveCaretAck();
   void OnSelectMessageAck();
@@ -142,10 +141,7 @@ private:
   };
   // Note: This function may result in |this| being deleted, and as such
   // should be the last method called in any internal chain of event handling.
-  void ProcessInputEventAck(blink::WebInputEvent::Type event_type,
-                            InputEventAckState ack_result,
-                            const ui::LatencyInfo& latency_info,
-                            AckSource ack_source);
+  void ProcessInputEventAck(const InputEventAck& ack, AckSource ack_source);

[jdduke (slow), 2015/05/07 21:11:15]

See comments in the .cc file, I guess until we propagate this to the external
world let's keep the arguments separate.

 
   // Dispatches the ack'ed event to |ack_handler_|.
   void ProcessKeyboardAck(blink::WebInputEvent::Type type,
@@ -169,7 +165,8 @@ private:
   // Forwards the event ack to |touch_event_queue_|, potentially triggering
   // dispatch of queued touch events, or the creation of gesture events.
   void ProcessTouchAck(InputEventAckState ack_result,
-                       const ui::LatencyInfo& latency);
+                       const ui::LatencyInfo& latency,
+                       const uint32 unique_touch_event_id);
 
   // Called when a touch timeout-affecting bit has changed, in turn toggling the
   // touch ack timeout feature of the |touch_event_queue_| as appropriate. Input