Discard compositor frames from unloaded web content

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/gpu/render_widget_compositor.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 1112 matching lines @@
 
 void RenderWidgetCompositor::SetDeviceColorSpace(
     const gfx::ColorSpace& color_space) {
   layer_tree_host_->SetDeviceColorSpace(color_space);
 }
 
 void RenderWidgetCompositor::SetIsForOopif(bool is_for_oopif) {
   is_for_oopif_ = is_for_oopif;
 }
 
+void RenderWidgetCompositor::SetContentSourceId(uint32_t id) {
+  layer_tree_host_->SetContentSourceId(id);
+}
+
 }  // namespace content