Add latency info to input events sent to RenderWidget.

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 9f809db8ff5cd87f6515ac352ab6e1fd64cc9bfd..5c9f91625ab113e4d68c5937f29f006cf4a19ce4 100644
--- a/content/browser/renderer_host/render_widget_host_impl.h
+++ b/content/browser/renderer_host/render_widget_host_impl.h
@@ -23,6 +23,7 @@
 #include "base/time.h"
 #include "base/timer.h"
 #include "build/build_config.h"
+#include "cc/debug/latency_info.h"
 #include "content/common/view_message_enums.h"
 #include "content/port/common/input_event_ack_state.h"
 #include "content/public/browser/render_widget_host.h"
@@ -67,6 +68,7 @@ class WebLayer;
 namespace content {
 class BackingStore;
 class GestureEventFilter;
+class GestureEventLatency;
 class MockRenderWidgetHost;
 class OverscrollController;
 class RenderWidgetHostDelegate;
@@ -253,7 +255,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   virtual void ForwardTouchEvent(const WebKit::WebTouchEvent& touch_event);
 
   // Forwards the given event immediately to the renderer.
-  void ForwardMouseEventImmediately(const WebKit::WebMouseEvent& mouse_event);
+  void ForwardMouseEventImmediately(const WebKit::WebMouseEvent& mouse_event,
+                                    const cc::LatencyInfo& latency_info);
   void ForwardTouchEventImmediately(const WebKit::WebTouchEvent& touch_event);
   void ForwardGestureEventImmediately(
       const WebKit::WebGestureEvent& gesture_event);
@@ -459,17 +462,45 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   // suppress_next_char_events_.
   void SuppressNextCharEvents();
 
+  void FrameSwapped(const cc::LatencyInfo& latency_info);
+
+  // Returns the ID that uniquely describes this component to the latency
+  // subsystem.
+  int64 GetLatencyComponentId();
+
+  class FrameSwappedObserver {

[piman, 2013/04/22 20:46:38]

There doesn't seem to be any implementation of this in this patch - is this
"FrameSwapped" infrastructure for a later patch? Can you remove it from this
one, so that we can review that part later, in context?

+   public:
+    virtual void OnFrameSwapped(RenderWidgetHostImpl* rwhi,
+                                const cc::LatencyInfo& latency_info) = 0;
+  };
+
+  void AddFrameSwappedObserver(FrameSwappedObserver* observer);
+  void RemoveFrameSwappedObserver(FrameSwappedObserver* observer);
+
  protected:
   virtual RenderWidgetHostImpl* AsRenderWidgetHostImpl() OVERRIDE;
 
   // Transmits the given input event. This is an internal helper for
   // |ForwardInputEvent()| and should not be used directly from elsewhere.
   void SendInputEvent(const WebKit::WebInputEvent& input_event,
-                      int event_size, bool is_keyboard_shortcut);
+                      int event_size, const cc::LatencyInfo& latency_info,
+                      bool is_keyboard_shortcut);
 
   // Internal implementation of the public Forward*Event() methods.
   void ForwardInputEvent(const WebKit::WebInputEvent& input_event,
-                         int event_size, bool is_keyboard_shortcut);
+                         int event_size, const cc::LatencyInfo& latency_info,
+                         bool is_keyboard_shortcut);
+
+  // Internal forwarding implementations that take a LatencyInfo.
+  virtual void ForwardMouseEventWithLatencyInfo(
+      const WebKit::WebMouseEvent& mouse_event,
+      const cc::LatencyInfo& latency_info);
+  virtual void ForwardWheelEventWithLatencyInfo(
+      const WebKit::WebMouseWheelEvent& wheel_event,
+      const cc::LatencyInfo& latency_info);
+
+  // Create a LatencyInfo struct for a new input event that was just received.
+  cc::LatencyInfo NewInputLatencyInfo();
 
   // Called when we receive a notification indicating that the renderer
   // process has gone. This will reset our state so that our state will be
@@ -740,13 +771,15 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   // The next mouse move event to send (only non-null while mouse_move_pending_
   // is true).
   scoped_ptr<WebKit::WebMouseEvent> next_mouse_move_;
+  cc::LatencyInfo next_mouse_move_latency_info_;
 
   // (Similar to |mouse_move_pending_|.) True if a mouse wheel event was sent
   // and we are waiting for a corresponding ack.
   bool mouse_wheel_pending_;
   WebKit::WebMouseWheelEvent current_wheel_event_;
 
-  typedef std::deque<WebKit::WebMouseWheelEvent> WheelEventQueue;
+  typedef std::deque<std::pair<WebKit::WebMouseWheelEvent, cc::LatencyInfo> >

[piman, 2013/04/22 20:46:38]

nit: rather than a std::pair, an explicit struct is a lot more readable at the
call sites ("event", "latency_info" as fields instead of "first" and "second")

+      WheelEventQueue;
 
   // (Similar to |next_mouse_move_|.) The next mouse wheel events to send.
   // Unlike mouse moves, mouse wheel events received while one is pending are
@@ -878,6 +911,10 @@ class CONTENT_EXPORT RenderWidgetHostImpl : virtual public RenderWidgetHost,
   // List of callbacks for pending snapshot requests to the renderer.
   std::queue<base::Callback<void(bool, const SkBitmap&)> > pending_snapshots_;
 
+  int64 last_input_number_;
+
+  ObserverList<FrameSwappedObserver> frame_swapped_observer_list_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };