Stop sending an async touchmove for the app slop region

content/browser/renderer_host/input/touch_event_queue_unittest.cc

Index: content/browser/renderer_host/input/touch_event_queue_unittest.cc
diff --git a/content/browser/renderer_host/input/touch_event_queue_unittest.cc b/content/browser/renderer_host/input/touch_event_queue_unittest.cc
index 21895d2935c7f0150262eba792821ee9be57ca4a..6d75aedd09189aca8cabd2a36978d1e5e765e4c3 100644
--- a/content/browser/renderer_host/input/touch_event_queue_unittest.cc
+++ b/content/browser/renderer_host/input/touch_event_queue_unittest.cc
@@ -1936,6 +1936,45 @@ TEST_F(TouchEventQueueTest, AsyncTouchThrottledAfterScroll) {
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
 }
 
+TEST_F(TouchEventQueueTest, AsyncTouchDeferredDuringTouchAck) {
+  SetTouchScrollingMode(TouchEventQueue::TOUCH_SCROLLING_MODE_ASYNC_TOUCHMOVE);
+
+  // Initiate scroll-induced touch throttling.
+  PressTouchPoint(0, 0);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(1U, GetAndResetAckedEventCount());
+
+  MoveTouchPoint(0, 0, 5);
+  EXPECT_EQ(1U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+  SendGestureEvent(WebInputEvent::GestureScrollBegin);
+  SendGestureEvent(WebInputEvent::GestureScrollUpdate);
+
+  // Now queue a touchmove that exceeds the application slop region.
+  MoveTouchPoint(0, 0, 20);
+  EXPECT_FALSE(HasPendingAsyncTouchMove());
+  EXPECT_EQ(2U, queued_event_count());
+  EXPECT_EQ(0U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+
+  // Despite the second touchmove exceeding the application slop region, its
+  // sending will be deferred until after the original touch was ack'ed.
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_TRUE(HasPendingAsyncTouchMove());
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(0U, GetAndResetSentEventCount());
+  EXPECT_EQ(2U, GetAndResetAckedEventCount());
+
+  // A subsequent touchmove will flush the deferred async touchmove,

[Rick Byers, 2015/01/27 17:59:15]

coalescing means it's more like 'replace' than 'flush', right?  Perhaps it's
worth having the test check the co-ordinate of the event here, verifying
coalescing occurred?

+  MoveTouchPoint(0, 0, 25);
+  EXPECT_FALSE(HasPendingAsyncTouchMove());
+  EXPECT_FALSE(sent_event().cancelable);
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+}
+
 // Ensure that async touch dispatch and touch ack timeout interactions work
 // appropriately.
 TEST_F(TouchEventQueueTest, AsyncTouchWithAckTimeout) {