Update from https://crrev.com/317530

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 1a18f9b72382edef19c0c70f952f27a25234060a..b6724b86154ac8dce6948aa4d0ac697bfb768384 100644
--- a/ui/events/latency_info.h
+++ b/ui/events/latency_info.h
@@ -25,26 +25,25 @@ enum LatencyComponentType {
   // Timestamp when a scroll update for the main thread is begun.
   INPUT_EVENT_LATENCY_BEGIN_SCROLL_UPDATE_MAIN_COMPONENT,
   // ---------------------------NORMAL COMPONENT-------------------------------
-  // Timestamp when the scroll update gesture event is sent from RWH to
-  // renderer. In Aura, touch event's LatencyInfo is carried over to the gesture
-  // event. So gesture event's INPUT_EVENT_LATENCY_RWH_COMPONENT is the
-  // timestamp when its original touch events is sent from RWH to renderer.
-  // In non-aura platform, INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT
-  // is the same as INPUT_EVENT_LATENCY_RWH_COMPONENT.
-  INPUT_EVENT_LATENCY_SCROLL_UPDATE_RWH_COMPONENT,
   // The original timestamp of the touch event which converts to scroll update.
   INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
+  // The original timestamp of the touch event which converts to the *first*
+  // scroll update in a scroll gesture sequence.
+  INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
   // Original timestamp for input event (e.g. timestamp from kernel).
   INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
   // Timestamp when the UI event is created.
   INPUT_EVENT_LATENCY_UI_COMPONENT,
   // This is special component indicating there is rendering scheduled for
-  // the event associated with this LatencyInfo.
-  INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_COMPONENT,
+  // the event associated with this LatencyInfo on main thread.
+  INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_MAIN_COMPONENT,
+  // This is special component indicating there is rendering scheduled for
+  // the event associated with this LatencyInfo on impl thread.
+  INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_IMPL_COMPONENT,
   // Timestamp when a scroll update is forwarded to the main thread.
   INPUT_EVENT_LATENCY_FORWARD_SCROLL_UPDATE_TO_MAIN_COMPONENT,
-  // Timestamp when the touch event is acked.
-  INPUT_EVENT_LATENCY_ACKED_TOUCH_COMPONENT,
+  // Timestamp when the event's ack is received by the RWH.
+  INPUT_EVENT_LATENCY_ACK_RWH_COMPONENT,
   // Frame number when a window snapshot was requested. The snapshot
   // is taken when the rendering results actually reach the screen.
   WINDOW_SNAPSHOT_FRAME_NUMBER_COMPONENT,
@@ -54,12 +53,13 @@ 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 Browser process began swap buffers
-  INPUT_EVENT_BROWSER_SWAP_BUFFER_COMPONENT,
+  // Timestamp when the frame is swapped in renderer.
+  INPUT_EVENT_LATENCY_RENDERER_SWAP_COMPONENT,
+  // Timestamp of when the browser process receives a buffer swap notification
+  // from the renderer.
+  INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT,
   // Timestamp of when the gpu service began swap buffers, unlike
-  // INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT which measure after
+  // 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.
@@ -111,7 +111,7 @@ struct EVENTS_BASE_EXPORT LatencyInfo {
   };
 
   // Empirically determined constant based on a typical scroll sequence.
-  enum { kTypicalMaxComponentsPerLatencyInfo = 9 };
+  enum { kTypicalMaxComponentsPerLatencyInfo = 10 };
 
   enum { kMaxInputCoordinates = 2 };