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

content/common/input/input_event_ack.h

 // Copyright 2015 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.
 
 #ifndef CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_H_
 #define CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "content/common/content_export.h"
+#include "content/common/input/input_event_ack_source.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/blink/did_overscroll_params.h"
 #include "ui/events/latency_info.h"
 
 namespace content {
 
 // InputEventAck.
 struct CONTENT_EXPORT InputEventAck {
-  InputEventAck(blink::WebInputEvent::Type type,
+  InputEventAck(InputEventAckSource source,
+                blink::WebInputEvent::Type type,
                 InputEventAckState state,
                 const ui::LatencyInfo& latency,
                 std::unique_ptr<ui::DidOverscrollParams> overscroll,
                 uint32_t unique_touch_event_id);
-  InputEventAck(blink::WebInputEvent::Type type,
+  InputEventAck(InputEventAckSource source,
+                blink::WebInputEvent::Type type,
                 InputEventAckState state,
                 const ui::LatencyInfo& latency,
                 uint32_t unique_touch_event_id);
-  InputEventAck(blink::WebInputEvent::Type type,
+  InputEventAck(InputEventAckSource source,
+                blink::WebInputEvent::Type type,
                 InputEventAckState state,
                 uint32_t unique_touch_event_id);
-  InputEventAck(blink::WebInputEvent::Type type, InputEventAckState state);
+  InputEventAck(InputEventAckSource source,
+                blink::WebInputEvent::Type type,
+                InputEventAckState state);
   InputEventAck();
   ~InputEventAck();
 
+  InputEventAckSource source;
   blink::WebInputEvent::Type type;
   InputEventAckState state;
   ui::LatencyInfo latency;
   std::unique_ptr<ui::DidOverscrollParams> overscroll;
   uint32_t unique_touch_event_id;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_H_