Remove dead paint flush tracking code.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 71831f671e0a01183537dfb26ba38e6d6ccc1731..9cf92a6a88247150d1f03d936f010ae746cd3c51 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -775,9 +775,6 @@ void RenderWidget::DidCompletePageScaleAnimation() {}
 void RenderWidget::DidReceiveCompositorFrameAck() {
   TRACE_EVENT0("renderer", "RenderWidget::DidReceiveCompositorFrameAck");
 
-  // Notify subclasses threaded composited rendering was flushed to the screen.
-  DidFlushPaint();
-
   if (!next_paint_flags_ && !need_update_rect_for_auto_resize_) {
     return;
   }
@@ -1691,11 +1688,6 @@ bool RenderWidget::SetDeviceColorProfile(
 void RenderWidget::OnOrientationChange() {
 }
 
-void RenderWidget::DidFlushPaint() {
-  if (owner_delegate_)
-    owner_delegate_->RenderWidgetDidFlushPaint();
-}
-
 void RenderWidget::SetHidden(bool hidden) {
   if (is_hidden_ == hidden)
     return;