Add more WebRuntimeFeatures plumbing for fast text autosizing

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 51 matching lines @@
 
     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 enableExperimentalCanvasFeatures(bool);
     BLINK_EXPORT static bool isExperimentalCanvasFeaturesEnabled();
 
+    BLINK_EXPORT static void enableFastTextAutosizing(bool);
+    BLINK_EXPORT static bool isFastTextAutosizingEnabled();
+
     BLINK_EXPORT static void enableFileSystem(bool);
     BLINK_EXPORT static bool isFileSystemEnabled();
 
     BLINK_EXPORT static void enableFullscreen(bool);
     BLINK_EXPORT static bool isFullscreenEnabled();
 
     BLINK_EXPORT static void enableGamepad(bool);
     BLINK_EXPORT static bool isGamepadEnabled();
 
     BLINK_EXPORT static void enableGeolocation(bool);
@@ skipping 68 matching lines @@
 
     BLINK_EXPORT static void enableOverlayFullscreenVideo(bool);
 
 private:
     WebRuntimeFeatures();
 };
 
 } // namespace WebKit
 
 #endif