[scheduler] Throttle background frames with 1% CPU limit

third_party/WebKit/public/web/WebRuntimeFeatures.h

 /*
  * Copyright (C) 2013 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 111 matching lines @@
     BLINK_EXPORT static void enableWebFontsInterventionTrigger(bool);
     BLINK_EXPORT static void enableWebGLDraftExtensions(bool);
     BLINK_EXPORT static void enableWebGLImageChromium(bool);
     BLINK_EXPORT static void enableWebUsb(bool);
     BLINK_EXPORT static void enableWebVR(bool);
     BLINK_EXPORT static void enableXSLT(bool);
     BLINK_EXPORT static void forceOverlayFullscreenVideo(bool);
     BLINK_EXPORT static void enableAutoplayMutedVideos(bool);
     BLINK_EXPORT static void enableTimerThrottlingForBackgroundTabs(bool);
     BLINK_EXPORT static void enableTimerThrottlingForHiddenFrames(bool);
+    BLINK_EXPORT static void enableExpensiveBackgroundTimerThrottling(bool);
     BLINK_EXPORT static void enableCanvas2dDynamicRenderingModeSwitching(bool);
     BLINK_EXPORT static void enableSendBeaconThrowForBlobWithNonSimpleType(bool);
 private:
     WebRuntimeFeatures();
 };
 
 } // namespace blink
 
 #endif