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

content/browser/renderer_host/input/input_router_impl.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 "content/browser/renderer_host/input/input_router_impl.h"
 
 #include <math.h>
 
 #include <utility>
 
@@ skipping 420 matching lines @@
     // renderer. Consequently, such event types should not affect event time
     // or in-flight event count metrics.
     if (dispatch_type == InputEventDispatchType::DISPATCH_TYPE_BLOCKING)
       client_->IncrementInFlightEventCount(input_event.type);
     return true;
   }
   return false;
 }
 
 void InputRouterImpl::OnInputEventAck(const InputEventAck& ack) {
-  client_->DecrementInFlightEventCount();
+  client_->DecrementInFlightEventCount(ack.source);
 
   if (ack.overscroll) {
     DCHECK(ack.type == WebInputEvent::MouseWheel ||
            ack.type == WebInputEvent::GestureScrollUpdate);
     OnDidOverscroll(*ack.overscroll);
   }
 
   ProcessInputEventAck(ack.type, ack.state, ack.latency,
                        ack.unique_touch_event_id, RENDERER);
 }
@@ skipping 175 matching lines @@
 
   flush_requested_ = false;
   client_->DidFlush();
 }
 
 void InputRouterImpl::SetFrameTreeNodeId(int frameTreeNodeId) {
   frame_tree_node_id_ = frameTreeNodeId;
 }
 
 }  // namespace content