Add synthetic delay points for latency testing

content/renderer/render_widget.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_widget.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
+#include "base/debug/trace_event_synthetic_delay.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
 #include "cc/debug/benchmark_instrumentation.h"
@@ skipping 1028 matching lines @@
   }
 
   base::TimeTicks start_time;
   if (base::TimeTicks::IsHighResNowFastAndReliable())
     start_time = base::TimeTicks::HighResNow();
 
   const char* const event_name =
       WebInputEventTraits::GetName(input_event->type);
   TRACE_EVENT1("renderer", "RenderWidget::OnHandleInputEvent",
                "event", event_name);
+  TRACE_EVENT_SYNTHETIC_DELAY_BEGIN("blink.HandleInputEvent");
 
   if (compositor_)
     compositor_->SetLatencyInfo(latency_info);
   else
     latency_info_.MergeWith(latency_info);
 
   base::TimeDelta now = base::TimeDelta::FromInternalValue(
       base::TimeTicks::Now().ToInternalValue());
 
   int64 delta = static_cast<int64>(
@@ skipping 112 matching lines @@
     Send(response);
   }
 
 #if defined(OS_ANDROID)
   // Allow the IME to be shown when the focus changes as a consequence
   // of a processed touch end event.
   if (input_event->type == WebInputEvent::TouchEnd && processed)
     UpdateTextInputState(true, true);
 #endif
 
+  TRACE_EVENT_SYNTHETIC_DELAY_END("blink.HandleInputEvent");
   handling_input_event_ = false;
 
   if (!prevent_default) {
     if (WebInputEvent::isKeyboardEventType(input_event->type))
       DidHandleKeyEvent();
     if (WebInputEvent::isMouseEventType(input_event->type))
       DidHandleMouseEvent(*(static_cast<const WebMouseEvent*>(input_event)));
     if (WebInputEvent::isTouchEventType(input_event->type))
       DidHandleTouchEvent(*(static_cast<const WebTouchEvent*>(input_event)));
   }
@@ skipping 1639 matching lines @@
           GetURLForGraphicsContext3D(),
           gpu_channel_host.get(),
           use_echo_for_swap_ack,
           attributes,
           false /* bind generates resources */,
           limits));
   return context.Pass();
 }
 
 }  // namespace content