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

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 2979 matching lines @@
                        dispatch_type != DISPATCH_TYPE_BLOCKING_NOTIFY_MAIN)) {
     return;
   }
 
   if (dispatch_type == DISPATCH_TYPE_BLOCKING_NOTIFY_MAIN) {
     NotifyInputEventHandled(input_event->type,
                             INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   }
 
   std::unique_ptr<InputEventAck> ack(
-      new InputEventAck(input_event->type, INPUT_EVENT_ACK_STATE_NOT_CONSUMED));
+      new InputEventAck(InputEventAckSource::MAIN_THREAD, input_event->type,
+                        INPUT_EVENT_ACK_STATE_NOT_CONSUMED));
   OnInputEventAck(std::move(ack));
 }
 
 }  // namespace content