Coalesce async touch move events until the ack back from render

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

Index: content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc b/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
index aba2b57322ef07d0fe0960cff38befe6ac9c07b5..bc8c1856769d7c238a12bef340e007f42f59ca97 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura_unittest.cc
@@ -443,9 +443,16 @@ class RenderWidgetHostViewAuraTest : public testing::Test {
 
   void SendInputEventACK(WebInputEvent::Type type,
       InputEventAckState ack_result) {
-    InputHostMsg_HandleInputEvent_ACK_Params ack;
-    ack.type = type;
-    ack.state = ack_result;
+    DCHECK(!WebInputEvent::isTouchEventType(type));
+    InputEventAck ack(type, ack_result);
+    InputHostMsg_HandleInputEvent_ACK response(0, ack);
+    widget_host_->OnMessageReceived(response);
+  }
+
+  void SendTouchEventACK(WebInputEvent::Type type, uint32 event_id,
+      InputEventAckState ack_result) {
+    DCHECK(WebInputEvent::isTouchEventType(type));
+    InputEventAck ack(type, ack_result, event_id);
     InputHostMsg_HandleInputEvent_ACK response(0, ack);
     widget_host_->OnMessageReceived(response);
   }
@@ -466,10 +473,23 @@ class RenderWidgetHostViewAuraTest : public testing::Test {
       return;
     }
 
-    if (WebInputEventTraits::IgnoresAckDisposition(*get<0>(params)))
+    if (!WebInputEventTraits::WillReceiveAckFromRenderer(*get<0>(params)))
       return;
 
-    SendInputEventACK(get<0>(params)->type, ack_result);
+    SendTouchEventACK(get<0>(params)->type, LastSentEventID(), ack_result);
+  }
+
+  uint32 LastSentEventID() {
+    uint32 last_sent_event_id = 0;

[jdduke (slow), 2015/05/12 16:07:11]

Again, I don't think we should use this logic. Let's either cache the id when we
send it, or make it available somehow each time we send the event.

[lanwei, 2015/05/13 21:01:53]

Done.

+    size_t count = sink_->message_count();
+    DCHECK_GT(count, 0U);
+    for (size_t i = 0; i < count; ++i) {
+      const WebInputEvent* input_event =
+          GetInputEventFromMessage(*sink_->GetMessageAt(i));
+      last_sent_event_id =
+          WebInputEventTraits::GetUniqueTouchEventId(*input_event);
+    }
+    return last_sent_event_id;
   }
 
  protected:
@@ -1102,9 +1122,9 @@ TEST_F(RenderWidgetHostViewAuraTest, TouchEventState) {
   widget_host_->OnMessageReceived(ViewHostMsg_HasTouchEventHandlers(0, false));
 
   // Ack'ing the outstanding event should flush the pending touch queue.
-  InputHostMsg_HandleInputEvent_ACK_Params ack;
-  ack.type = blink::WebInputEvent::TouchStart;
-  ack.state = INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+  InputEventAck ack(blink::WebInputEvent::TouchStart,
+                    INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS,
+                    press.unique_event_id());
   widget_host_->OnMessageReceived(InputHostMsg_HandleInputEvent_ACK(0, ack));
   EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
 
@@ -2780,14 +2800,14 @@ TEST_F(RenderWidgetHostViewAuraOverscrollTest, OverscrollWithTouchEvents) {
 
   // The test sends an intermingled sequence of touch and gesture events.
   PressTouchPoint(0, 1);

[jdduke (slow), 2015/05/12 16:07:11]

Looks like only 2 methods use the |PressTouchPoint| helper methods. I'd be OK
getting rid of them entirely and just storing the SyntheticWebTochEvent here, or
have the helper methods return the id (you'll need to cache it before the points
are reset).

[lanwei, 2015/05/13 21:01:53]

Done.

-  SendInputEventACK(WebInputEvent::TouchStart,
+  SendTouchEventACK(WebInputEvent::TouchStart, LastSentEventID(),
                     INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
 
   MoveTouchPoint(0, 20, 5);
-  EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
-  SendInputEventACK(WebInputEvent::TouchMove,
+  SendTouchEventACK(WebInputEvent::TouchMove, LastSentEventID(),
                     INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
 
   EXPECT_EQ(OVERSCROLL_NONE, overscroll_mode());
   EXPECT_EQ(OVERSCROLL_NONE, overscroll_delegate()->current_mode());
@@ -3312,13 +3332,13 @@ TEST_F(RenderWidgetHostViewAuraTest, CorrectNumberOfAcksAreDispatched) {
       ui::ET_TOUCH_PRESSED, gfx::Point(30, 30), 0, ui::EventTimeForNow());
 
   view_->OnTouchEvent(&press1);
-  SendInputEventACK(blink::WebInputEvent::TouchStart,
+  SendTouchEventACK(blink::WebInputEvent::TouchStart, press1.unique_event_id(),
                     INPUT_EVENT_ACK_STATE_CONSUMED);
 
   ui::TouchEvent press2(
       ui::ET_TOUCH_PRESSED, gfx::Point(20, 20), 1, ui::EventTimeForNow());
   view_->OnTouchEvent(&press2);
-  SendInputEventACK(blink::WebInputEvent::TouchStart,
+  SendTouchEventACK(blink::WebInputEvent::TouchStart, press2.unique_event_id(),
                     INPUT_EVENT_ACK_STATE_CONSUMED);
 
   EXPECT_EQ(2U, view_->dispatcher_->processed_touch_event_count());