[scheduler] Use Finch to control background throttling.

third_party/WebKit/Source/web/WebViewImpl.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 731 matching lines @@
 
   // This is owned by the LayerTreeHostImpl, and should only be used on the
   // compositor thread. The LayerTreeHostImpl is indirectly owned by this
   // class so this pointer should be valid until this class is destructed.
   CrossThreadPersistent<CompositorMutatorImpl> m_mutator;
 
   Persistent<EventListener> m_popupMouseWheelEventListener;
 
   WebPageImportanceSignals m_pageImportanceSignals;
 
-  const std::unique_ptr<WebViewScheduler> m_scheduler;
+  std::unique_ptr<WebViewScheduler> m_scheduler;
 
   double m_lastFrameTimeMonotonic;
 
   // TODO(lfg): This is used in order to disable compositor visibility while
   // the page is still visible. This is needed until the WebView and WebWidget
   // split is complete, since in out-of-process iframes the page can be
   // visible, but the WebView should not be used as a widget.
   bool m_overrideCompositorVisibility;
 
   Persistent<ResizeViewportAnchor> m_resizeViewportAnchor;
 };
 
 // We have no ways to check if the specified WebView is an instance of
 // WebViewImpl because WebViewImpl is the only implementation of WebView.
 DEFINE_TYPE_CASTS(WebViewImpl, WebView, webView, true, true);
 
 }  // namespace blink
 
 #endif