Add a public API to enable/disable blink runtime features by name

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 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebRuntimeFeatures_h
 #define WebRuntimeFeatures_h
 
 #include "../platform/WebCommon.h"
 
 namespace WebKit {
 
+class WebString;
+
 // This class is used to enable runtime features of Blink.
 // All features are disabled by default.
 // Most clients should call enableStableFeatures() to enable
 // features Blink has made API commitments to.
 class WebRuntimeFeatures {
 public:
     WEBKIT_EXPORT static void enableStableFeatures(bool);
     WEBKIT_EXPORT static void enableExperimentalFeatures(bool);
     WEBKIT_EXPORT static void enableTestOnlyFeatures(bool);
+    WEBKIT_EXPORT static bool setFeatureEnabled(const WebString&, bool);
 
     // FIXME: Delete after removing all callers in Content.
     static void enableFullScreenAPI(bool enable) { enableFullscreen(enable); }
     static void enableIndexedDatabase(bool enable) { enableIndexedDB(enable); }
 
     WEBKIT_EXPORT static void enableApplicationCache(bool);
     WEBKIT_EXPORT static bool isApplicationCacheEnabled();
 
     WEBKIT_EXPORT static void enableCanvasPath(bool);
     WEBKIT_EXPORT static bool isCanvasPathEnabled();
@@ skipping 151 matching lines @@
     WEBKIT_EXPORT static void enableInputTypeColor(bool);
     WEBKIT_EXPORT static bool isInputTypeColorEnabled();
 
 private:
     WebRuntimeFeatures();
 };
 
 } // namespace WebKit
 
 #endif