Expose a public API option to force 2D canvas to use display lists

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 34 matching lines @@
     BLINK_EXPORT static void enableApplicationCache(bool);
 
     BLINK_EXPORT static void enableDatabase(bool);
 
     BLINK_EXPORT static void enableCompositedSelectionUpdate(bool);
     BLINK_EXPORT static bool isCompositedSelectionUpdateEnabled();
 
     BLINK_EXPORT static void enableDecodeToYUV(bool);
 
     BLINK_EXPORT static void enableDisplayList2dCanvas(bool);
+    BLINK_EXPORT static void forceDisplayList2dCanvas(bool);
 
     BLINK_EXPORT static void enableEncryptedMedia(bool);
     BLINK_EXPORT static bool isEncryptedMediaEnabled();
 
     BLINK_EXPORT static void enablePrefixedEncryptedMedia(bool);
     BLINK_EXPORT static bool isPrefixedEncryptedMediaEnabled();
 
     BLINK_EXPORT static void enableBleedingEdgeFastPaths(bool);
 
     BLINK_EXPORT static void enableBlinkScheduler(bool);
@@ skipping 80 matching lines @@
 
     BLINK_EXPORT static void enableSVG1DOM(bool);
 
 private:
     WebRuntimeFeatures();
 };
 
 } // namespace blink
 
 #endif