Devtools: make DOM traversal utilities climb shadow tree.

Source/devtools/front_end/source_frame/CodeMirrorTextEditor.js

 /*
  * Copyright (C) 2012 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 732 matching lines @@
         };
     },
 
     /**
      * @param {number} x
      * @param {number} y
      * @return {?WebInspector.TextRange}
      */
     coordinatesToCursorPosition: function(x, y)
     {
-        var element = document.elementFromPoint(x, y);
+        var element = document.deepElementFromPoint(x, y);
         if (!element || !element.isSelfOrDescendant(this._codeMirror.getWrapperElement()))
             return null;
         var gutterBox = this._codeMirror.getGutterElement().boxInWindow();
         if (x >= gutterBox.x && x <= gutterBox.x + gutterBox.width &&
             y >= gutterBox.y && y <= gutterBox.y + gutterBox.height)
             return null;
         var coords = this._codeMirror.coordsChar({left: x, top: y});
         return WebInspector.CodeMirrorUtils.toRange(coords, coords);
     },
 
@@ skipping 1670 matching lines @@
     function tokenOverride(superToken, stream, state)
     {
         var token = superToken(stream, state);
         return token ? tokenPrefix + token.split(/ +/).join(" " + tokenPrefix) : token;
     }
 }
 
 WebInspector.CodeMirrorTextEditor._overrideModeWithPrefixedTokens("css", "css-");
 WebInspector.CodeMirrorTextEditor._overrideModeWithPrefixedTokens("javascript", "js-");
 WebInspector.CodeMirrorTextEditor._overrideModeWithPrefixedTokens("xml", "xml-");