Add new latency_info for tracking browser composite time.

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 3b9d6e52bb88f63e351a91d7ffbbd4f610395dce..ab660c1dc59daacaea0425fc83c024558558d2e8 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/time.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
+#include "cc/base/rolling_time_delta_history.h"
 #include "cc/resources/shared_bitmap.h"
 #include "content/browser/renderer_host/event_with_latency_info.h"
 #include "content/browser/renderer_host/input/input_ack_handler.h"
@@ -483,6 +484,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl
   // or create it if it doesn't already exist.
   BrowserAccessibilityManager* GetOrCreateRootBrowserAccessibilityManager();
 
+  base::TimeDelta GetEstimatedBrowserCompositeTime();
+
 #if defined(OS_WIN)
   gfx::NativeViewAccessible GetParentNativeViewAccessible();
 #endif
@@ -846,6 +849,8 @@ class CONTENT_EXPORT RenderWidgetHostImpl
       base::Callback<void(const unsigned char*, size_t)> > PendingSnapshotMap;
   PendingSnapshotMap pending_browser_snapshots_;
 
+  cc::RollingTimeDeltaHistory browser_composite_latency_history_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };