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

cc/surfaces/display.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 "cc/surfaces/display.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 189 matching lines @@
     renderer_->DecideRenderPassAllocationsForFrame(
         frame_data->render_pass_list);
     renderer_->DrawFrame(&frame_data->render_pass_list, device_scale_factor_,
                          device_viewport_rect, device_clip_rect,
                          disable_picture_quad_image_filtering);
   }
 
   if (should_draw && !avoid_swap) {
     swapped_since_resize_ = true;
     for (auto& latency : frame->metadata.latency_info) {
+      TRACE_EVENT_WITH_FLOW0("toplevel", "Display::DrawAndSwap",
+                             TRACE_ID_DONT_MANGLE(latency.trace_id),
+                             TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT);
       TRACE_EVENT_FLOW_STEP0(
           "input,benchmark",
           "LatencyInfo.Flow",
           TRACE_ID_DONT_MANGLE(latency.trace_id),
           "Display::DrawAndSwap");
     }
     benchmark_instrumentation::IssueDisplayRenderingStatsEvent();
     renderer_->SwapBuffers(frame->metadata);
   } else {
     stored_latency_info_.insert(stored_latency_info_.end(),
@@ skipping 78 matching lines @@
 
   if (surface_id == current_surface_id_)
     UpdateRootSurfaceResourcesLocked();
 }
 
 SurfaceId Display::CurrentSurfaceId() {
   return current_surface_id_;
 }
 
 }  // namespace cc