Defer flushing the touch queue when all touch handlers removed

content/browser/renderer_host/input/input_router_impl_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <math.h>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 601 matching lines @@
 
   SendInputEventACK(WebInputEvent::TouchMove,
                     INPUT_EVENT_ACK_STATE_CONSUMED);
   EXPECT_TRUE(TouchEventQueueEmpty());
   EXPECT_EQ(1U, ack_handler_->GetAndResetAckCount());
   EXPECT_EQ(WebInputEvent::TouchMove,
             ack_handler_->acked_touch_event().event.type);
   EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
 }
 
-// Tests that the touch-queue is emptied if a page stops listening for touch
-// events.
+// Tests that the touch-queue is emptied after a page stops listening for touch
+// events and the outstanding ack is received.
 TEST_F(InputRouterImplTest, TouchEventQueueFlush) {
   OnHasTouchEventHandlers(true);
   EXPECT_TRUE(client_->has_touch_handler());
   EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
   EXPECT_TRUE(TouchEventQueueEmpty());
 
   EXPECT_TRUE(input_router_->ShouldForwardTouchEvent());
 
   // Send a touch-press event.
   PressTouchPoint(1, 1);
   SendTouchEvent();
+  MoveTouchPoint(0, 2, 2);
+  MoveTouchPoint(0, 3, 3);
   EXPECT_FALSE(TouchEventQueueEmpty());
   EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
 
-  // The page stops listening for touch-events. The touch-event queue should now
-  // be emptied, but none of the queued touch-events should be sent to the
-  // renderer.
+  // The page stops listening for touch-events. Note that flushing is deferred
+  // until the outstanding ack is received.
   OnHasTouchEventHandlers(false);
   EXPECT_FALSE(client_->has_touch_handler());
   EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
+  EXPECT_FALSE(TouchEventQueueEmpty());
+  EXPECT_TRUE(input_router_->ShouldForwardTouchEvent());
+
+  // After the ack, the touch-event queue should be empty, and none of the
+  // flushed touch-events should have been sent to the renderer.
+  SendInputEventACK(WebInputEvent::TouchStart, INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
   EXPECT_TRUE(TouchEventQueueEmpty());
   EXPECT_FALSE(input_router_->ShouldForwardTouchEvent());
 }
 
 #if defined(USE_AURA)
 // Tests that the acked events have correct state. (ui::Events are used only on
 // windows and aura)
 TEST_F(InputRouterImplTest, AckedTouchEventState) {
   input_router_->OnMessageReceived(ViewHostMsg_HasTouchEventHandlers(0, true));
   EXPECT_EQ(0U, GetSentMessageCountAndResetSink());
@@ skipping 1062 matching lines @@
   client_overscroll = client_->GetAndResetOverscroll();
   EXPECT_EQ(wheel_overscroll.accumulated_overscroll,
             client_overscroll.accumulated_overscroll);
   EXPECT_EQ(wheel_overscroll.latest_overscroll_delta,
             client_overscroll.latest_overscroll_delta);
   EXPECT_EQ(wheel_overscroll.current_fling_velocity,
             client_overscroll.current_fling_velocity);
 }
 
 }  // namespace content