Add animation support for WebP images

public/webpage/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 193 matching lines @@
 
     WEBKIT_EXPORT static void enableWebPInAcceptHeader(bool);
     WEBKIT_EXPORT static bool isWebPInAcceptHeaderEnabled();
 
     WEBKIT_EXPORT static void enableDataListElement(bool);
     WEBKIT_EXPORT static bool isDataListElementEnabled();
 
     WEBKIT_EXPORT static void enableInputTypeColor(bool);
     WEBKIT_EXPORT static bool isInputTypeColorEnabled();
 
+    WEBKIT_EXPORT static void enableAnimatedWebP(bool);
+    WEBKIT_EXPORT static bool isAnimatedWebPEnabled();
+
 private:
     WebRuntimeFeatures();
 };
 
 } // namespace WebKit
 
 #endif