Notify DevTools when updating frame in RenderWidget

Add a call to WebWidget::instrumentBeginFrame() in
RenderWiddget::doDeferredUpdate() so DevTools can mark
frames on timeline.

Related issue upstream:
https://bugs.webkit.org/show_bug.cgi?id=80127

BUG=none
TEST=none

Review URL: https://chromiumcodereview.appspot.com/9592006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@126921 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/render_widget.cc

@@ -829,6 +829,7 @@ void RenderWidget::DoDeferredUpdate() {
 
   // Tracking of frame rate jitter
   base::TimeTicks frame_begin_ticks = base::TimeTicks::Now();
+  webwidget_->instrumentBeginFrame();
   AnimateIfNeeded();
 
   // Layout may generate more invalidation.  It may also enable the
@@ -846,6 +847,7 @@ void RenderWidget::DoDeferredUpdate() {
   // animations running layout as these may generate further invalidations.
   if (!paint_aggregator_.HasPendingUpdate()) {
     TRACE_EVENT0("renderer", "EarlyOut_NoPendingUpdate");
+    webwidget_->instrumentCancelFrame();
     return;
   }