Reland "Add new latency_info for tracking browser composite time."

ui/events/latency_info.h

Index: ui/events/latency_info.h
diff --git a/ui/events/latency_info.h b/ui/events/latency_info.h
index e3000e16d50f503dfcf614579df871b40b1f3f93..78892d042e92dbc04f0117f0e20d7d17a567cbb2 100644
--- a/ui/events/latency_info.h
+++ b/ui/events/latency_info.h
@@ -54,6 +54,11 @@ enum LatencyComponentType {
   WINDOW_OLD_SNAPSHOT_FRAME_NUMBER_COMPONENT,
   // Timestamp when a tab is requested to be shown.
   TAB_SHOW_COMPONENT,
+  // Timestamp of when the Browser process began compositing.
+  INPUT_EVENT_BROWSER_COMPOSITE_COMPONENT,
+  // Timestamp of when the gpu service began swap buffers, unlike
+  // INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT which measures after.
+  INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT,
   // ---------------------------TERMINAL COMPONENT-----------------------------
   // TERMINAL COMPONENT is when we show the latency end in chrome://tracing.
   // Timestamp when the mouse event is acked from renderer and it does not
@@ -104,7 +109,7 @@ struct EVENTS_BASE_EXPORT LatencyInfo {
   };
 
   // Empirically determined constant based on a typical scroll sequence.
-  enum { kTypicalMaxComponentsPerLatencyInfo = 7 };
+  enum { kTypicalMaxComponentsPerLatencyInfo = 9 };
 
   enum { kMaxInputCoordinates = 2 };