Add UMA metric for tracking listeners for blocking touch while fling is happening

content/renderer/input/input_handler_manager_client.h

 // 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.
 
 #ifndef CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_CLIENT_H_
 #define CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_CLIENT_H_
 
 #include "base/callback.h"
 #include "base/callback_forward.h"
 #include "base/macros.h"
@@ skipping 30 matching lines @@
                          ui::LatencyInfo* latency_info)> Handler;
 
   // Called from the main thread.
   virtual void SetBoundHandler(const Handler& handler) = 0;
 
   // Called from the compositor thread.
   virtual void DidAddInputHandler(int routing_id) = 0;
   virtual void DidRemoveInputHandler(int routing_id) = 0;
   virtual void DidOverscroll(int routing_id,
                              const DidOverscrollParams& params) = 0;
+  virtual void DidStartFlinging(int routing_id) = 0;
   virtual void DidStopFlinging(int routing_id) = 0;
   virtual void NotifyInputEventHandled(int routing_id,
                                        blink::WebInputEvent::Type type) = 0;
 
  protected:
   InputHandlerManagerClient() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InputHandlerManagerClient);
 };
@@ skipping 10 matching lines @@
  protected:
   SynchronousInputHandlerProxyClient() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SynchronousInputHandlerProxyClient);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_CLIENT_H_