Implement scroll handler latency tracking

ui/events/latency_info.cc

 // 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.
 
 #include "base/debug/trace_event.h"
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/stringprintf.h"
 #include "ui/events/latency_info.h"
 
 #include <algorithm>
 
 namespace {
 
 const size_t kMaxLatencyInfoNumber = 100;
 
 const char* GetComponentName(ui::LatencyComponentType type) {
 #define CASE_TYPE(t) case ui::t:  return #t
   switch (type) {
     CASE_TYPE(INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_BEGIN_PLUGIN_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT);
+    CASE_TYPE(INPUT_EVENT_LATENCY_SCROLL_UPDATE_BLINK_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_UI_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_ACKED_TOUCH_COMPONENT);
     CASE_TYPE(WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT);
     CASE_TYPE(WINDOW_OLD_SNAPSHOT_FRAME_NUMBER_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_TERMINATED_MOUSE_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_TERMINATED_TOUCH_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_TERMINATED_GESTURE_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT);
@@ skipping 217 matching lines @@
 }
 
 void LatencyInfo::TraceEventType(const char* event_type) {
   TRACE_EVENT_ASYNC_STEP_INTO0("benchmark",
                                "InputLatency",
                                TRACE_ID_DONT_MANGLE(trace_id),
                                event_type);
 }
 
 }  // namespace ui