Implement scroll handler latency tracking

ui/events/latency_info.cc

Index: ui/events/latency_info.cc
diff --git a/ui/events/latency_info.cc b/ui/events/latency_info.cc
index f21cb1e12c4813a204da3863ff4b1e9a4095172c..4e817d06432107f2f6a45861ab30b39fefad0b68 100644
--- a/ui/events/latency_info.cc
+++ b/ui/events/latency_info.cc
@@ -19,11 +19,13 @@ const char* GetComponentName(ui::LatencyComponentType type) {
   switch (type) {
     CASE_TYPE(INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_BEGIN_PLUGIN_COMPONENT);
+    CASE_TYPE(INPUT_EVENT_LATENCY_BEGIN_SCROLL_UPDATE_MAIN_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_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_FORWARD_SCROLL_UPDATE_TO_MAIN_COMPONENT);
     CASE_TYPE(INPUT_EVENT_LATENCY_ACKED_TOUCH_COMPONENT);
     CASE_TYPE(WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT);
     CASE_TYPE(WINDOW_OLD_SNAPSHOT_FRAME_NUMBER_COMPONENT);
@@ -61,7 +63,8 @@ bool IsTerminalComponent(ui::LatencyComponentType type) {
 
 bool IsBeginComponent(ui::LatencyComponentType type) {
   return (type == ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT ||
-          type == ui::INPUT_EVENT_LATENCY_BEGIN_PLUGIN_COMPONENT);
+          type == ui::INPUT_EVENT_LATENCY_BEGIN_PLUGIN_COMPONENT ||
+          type == ui::INPUT_EVENT_LATENCY_BEGIN_SCROLL_UPDATE_MAIN_COMPONENT);
 }
 
 // This class is for converting latency info to trace buffer friendly format.