Add touch drag UMA latency metric.

content/browser/renderer_host/input/input_router_impl_perftest.cc

 // Copyright 2014 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 <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/renderer_host/input/input_ack_handler.h"
@@ skipping 63 matching lines @@
  public:
   NullInputRouterClient() {}
   ~NullInputRouterClient() override {}
 
   // InputRouterClient
   InputEventAckState FilterInputEvent(
       const blink::WebInputEvent& input_event,
       const ui::LatencyInfo& latency_info) override {
     return INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
   }
+  void OnForwardEventToRenderer(
+      const blink::WebInputEvent& event,
+      ui::LatencyInfo* latency) override {
+  }
+
   void IncrementInFlightEventCount() override {}
   void DecrementInFlightEventCount() override {}
   void OnHasTouchEventHandlers(bool has_handlers) override {}
   void DidFlush() override {}
   void DidOverscroll(const DidOverscrollParams& params) override {}
   void DidStopFlinging() override {}
 };
 
 class NullIPCSender : public IPC::Sender {
  public:
@@ skipping 285 matching lines @@
 
 TEST_F(InputRouterImplPerfTest, TouchSwipeToGestureScroll) {
   SimulateTouchAndScrollEventSequence("TouchSwipeToGestureScroll ",
                                       kDefaultSteps,
                                       kDefaultOrigin,
                                       kDefaultDistance,
                                       kDefaultIterations);
 }
 
 }  // namespace content