Implement a new flow event API that allows binding flow events and regular events.

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/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 1093 matching lines @@
   }
 #endif
 
   base::AutoReset<const ui::LatencyInfo*> resetter(&current_event_latency_info_,
                                                    &latency_info);
 
   base::TimeTicks start_time;
   if (base::TimeTicks::IsHighResolution())
     start_time = base::TimeTicks::Now();
 
-  TRACE_EVENT1("renderer,benchmark", "RenderWidget::OnHandleInputEvent",
+  TRACE_EVENT_WITH_FLOW1("renderer,benchmark", "RenderWidget::OnHandleInputEvent",
+               TRACE_ID_DONT_MANGLE(latency_info.trace_id),
+               TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT,
                "event", WebInputEventTraits::GetName(input_event->type));
   TRACE_EVENT_SYNTHETIC_DELAY_BEGIN("blink.HandleInputEvent");
   TRACE_EVENT_FLOW_STEP0(
       "input,benchmark",
       "LatencyInfo.Flow",
       TRACE_ID_DONT_MANGLE(latency_info.trace_id),
       "HanldeInputEventMain");
 
   // If we don't have a high res timer, these metrics won't be accurate enough
   // to be worth collecting. Note that this does introduce some sampling bias.
@@ skipping 1343 matching lines @@
 void RenderWidget::RegisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.AddObserver(frame);
 }
 
 void RenderWidget::UnregisterVideoHoleFrame(RenderFrameImpl* frame) {
   video_hole_frames_.RemoveObserver(frame);
 }
 #endif  // defined(VIDEO_HOLE)
 
 }  // namespace content