[DevTools] Make SourceFrame.setEditable work.

third_party/WebKit/Source/devtools/front_end/source_frame/SourceFrame.js

 /*
  * Copyright (C) 2011 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 49 matching lines @@
     this._shortcuts = {};
     this.element.addEventListener('keydown', this._handleKeyDown.bind(this), false);
 
     this._sourcePosition = new UI.ToolbarText();
 
     /**
      * @type {?UI.SearchableView}
      */
     this._searchableView = null;
     this._editable = false;
+    this._textEditor.setReadOnly(true);
   }
 
   /**
    * @param {boolean} editable
+   * @protected
    */
   setEditable(editable) {
     this._editable = editable;
-    this._textEditor.setReadOnly(editable);
+    this._textEditor.setReadOnly(!editable);
   }
 
   /**
    * @param {number} key
    * @param {function():boolean} handler
    */
   addShortcut(key, handler) {
     this._shortcuts[key] = handler;
   }
 
@@ skipping 484 matching lines @@
     }
   }
 
   _handleKeyDown(e) {
     var shortcutKey = UI.KeyboardShortcut.makeKeyFromEvent(e);
     var handler = this._shortcuts[shortcutKey];
     if (handler && handler())
       e.consume(true);
   }
 };