Don't restart the hang renderer timeout on messages ack'd from the compositor thread.

content/browser/renderer_host/input/main_thread_event_queue_browsertest.cc

 // Copyright 2016 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 <utility>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
@@ skipping 105 matching lines @@
         new InputMsgWatcher(GetWidgetHost(), blink::WebInputEvent::MouseMove));
     GetWidgetHost()->ForwardMouseEvent(SyntheticWebMouseEventBuilder::Build(
         blink::WebInputEvent::MouseMove, 10, 10, 0));
     GetWidgetHost()->ForwardMouseEvent(SyntheticWebMouseEventBuilder::Build(
         blink::WebInputEvent::MouseMove, 15, 15, 0));
     GetWidgetHost()->ForwardMouseEvent(SyntheticWebMouseEventBuilder::Build(
         blink::WebInputEvent::MouseMove, 20, 25, 0));
 
     // Runs until we get the InputMsgAck callback.
     EXPECT_EQ(INPUT_EVENT_ACK_STATE_CONSUMED, input_msg_watcher->WaitForAck());
+    EXPECT_EQ(InputEventAckSource::MAIN_THREAD,
+              static_cast<InputEventAckSource>(
+                  input_msg_watcher->last_event_ack_source()));
 
     int mouse_move_count = 0;
     while (mouse_move_count <= 0)
       mouse_move_count = ExecuteScriptAndExtractInt("window.mouseMoveCount");
     EXPECT_EQ(1, mouse_move_count);
 
     int last_mouse_x =
         ExecuteScriptAndExtractInt("window.lastMouseMoveEvent.x");
     int last_mouse_y =
         ExecuteScriptAndExtractInt("window.lastMouseMoveEvent.y");
@@ skipping 17 matching lines @@
                        blink::WebPointerProperties::Button::Left);
     scoped_refptr<InputMsgWatcher> input_msg_watcher(
         new InputMsgWatcher(GetWidgetHost(), blink::WebInputEvent::TouchMove));
 
     for (const auto& event : kEvents)
       GetWidgetHost()->ForwardEmulatedTouchEvent(event);
 
     // Runs until we get the InputMsgAck callback.
     EXPECT_EQ(INPUT_EVENT_ACK_STATE_SET_NON_BLOCKING,
               input_msg_watcher->WaitForAck());
+    EXPECT_EQ(InputEventAckSource::COMPOSITOR_THREAD,
+              static_cast<InputEventAckSource>(
+                  input_msg_watcher->last_event_ack_source()));
 
     int touch_move_count = 0;
     while (touch_move_count <= 0)
       touch_move_count = ExecuteScriptAndExtractInt("window.touchMoveCount");
     EXPECT_EQ(1, touch_move_count);
 
     int last_touch_x = ExecuteScriptAndExtractInt(
         "window.lastTouchMoveEvent.touches[0].pageX");
     int last_touch_y = ExecuteScriptAndExtractInt(
         "window.lastTouchMoveEvent.touches[0].pageY");
@@ skipping 15 matching lines @@
 #define MAYBE_TouchMove DISABLED_TouchMove
 #else
 #define MAYBE_TouchMove TouchMove
 #endif
 IN_PROC_BROWSER_TEST_F(MainThreadEventQueueBrowserTest, MAYBE_TouchMove) {
   LoadURL(kJankyPageURL);
   DoTouchMove();
 }
 
 }  // namespace content