Factor out latency tracking from RenderWidgetHostImpl

content/browser/renderer_host/render_widget_host_impl.h

Index: content/browser/renderer_host/render_widget_host_impl.h
diff --git a/content/browser/renderer_host/render_widget_host_impl.h b/content/browser/renderer_host/render_widget_host_impl.h
index 454bb17ffbbd957e0e77150b51ac82c0f9b7048f..d5cafda3c6a61621a6aea80eee37e07d10429f7e 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -29,6 +29,7 @@
 #include "content/browser/renderer_host/input/input_router_client.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
 #include "content/browser/renderer_host/input/touch_emulator_client.h"
+#include "content/browser/renderer_host/render_widget_host_latency_tracker.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/common/input/synthetic_gesture_packet.h"
 #include "content/common/view_message_enums.h"
@@ -466,11 +467,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl
       gfx::Size snapshot_size,
       scoped_refptr<base::RefCountedBytes> png_data);
 
-  // LatencyComponents generated in the renderer must have component IDs
-  // provided to them by the browser process. This function adds the correct
-  // component ID where necessary.
-  void AddLatencyInfoComponentIds(ui::LatencyInfo* latency_info);
-
   InputRouter* input_router() { return input_router_.get(); }
 
   // Get the BrowserAccessibilityManager for the root of the frame tree,
@@ -487,20 +483,6 @@ class CONTENT_EXPORT RenderWidgetHostImpl
  protected:
   RenderWidgetHostImpl* AsRenderWidgetHostImpl() override;
 
-  // Create a LatencyInfo struct with INPUT_EVENT_LATENCY_RWH_COMPONENT
-  // component if it is not already in |original|. And if |original| is
-  // not NULL, it is also merged into the resulting LatencyInfo.
-  ui::LatencyInfo CreateInputEventLatencyInfoIfNotExist(
-      const ui::LatencyInfo* original,
-      blink::WebInputEvent::Type type,
-      const ui::LatencyInfo::InputCoordinate* logical_coordinates,
-      size_t logical_coordinates_size);
-  // Add UMA histograms for the latency to the renderer and roundtrip latency
-  // for a given event type.
-  void ComputeInputLatencyHistograms(
-      blink::WebInputEvent::Type type,
-      const ui::LatencyInfo& latency_info) const;
-
   // Called when we receive a notification indicating that the renderer
   // process has gone. This will reset our state so that our state will be
   // consistent if a new renderer is created.
@@ -679,6 +661,9 @@ class CONTENT_EXPORT RenderWidgetHostImpl
                          InputEventAckState ack_result) override;
   void OnUnexpectedEventAck(UnexpectedEventAckType type) override;
 
+  void StartTrackingInputEventLatency(const blink::WebInputEvent& event,
+                                      ui::LatencyInfo* latency);
+
   void OnSyntheticGestureCompleted(SyntheticGesture::Result result);
 
   // Called when there is a new auto resize (using a post to avoid a stack
@@ -840,7 +825,7 @@ class CONTENT_EXPORT RenderWidgetHostImpl
   std::list<HWND> dummy_windows_for_activation_;
 #endif
 
-  int64 last_input_number_;
+  RenderWidgetHostLatencyTracker latency_tracker_;
 
   bool subscribe_uniform_enabled_;