Implementing directional selection strategy in Blink.

Source/core/editing/TextGranularity.h

 /*
  * Copyright (C) 2004 Apple Computer, 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 24 matching lines @@
     WordGranularity,
     SentenceGranularity,
     LineGranularity,
     ParagraphGranularity,
     SentenceBoundary,
     LineBoundary,
     ParagraphBoundary,
     DocumentBoundary
 };
 
+enum SelectionStrategy {
+    // Always using CharacterGranularity
+    StrategyDefault,
+    // Switches between WordGranularity and CharacterGranularity
+    // Depending on whether the selection or growing or shrinking
+    StrategyDirection,
+};
+
 }
 
 #endif