Fix missing sidebar in Chrome 34 and later

See facebook#29.

I updated blink-devtools to the latest (requires sebmarkbage/blink-devtools#1) and did a manual merge, changing ReactPanel.js to match all changes that happened to ElementPanel.js since the last devtools version.

I'm not sure we actually want to continue tracking the latest devtools; we could presumably keep an old version of the panels and just fix the specific problem with the removed SidebarView.

This doesn't actually work properly yet due to some style-related bug; when the panel is rendered, the View components read all of their dimensions as 0, then 0 is set as the actual width and height of each element, causing nothing to display. However, if the script debugger is used within `ReactPanel.show` to inspect `this.element` (but not to change any properties on it), then the panel seems to display correctly. I'm not sure how to go about fixing this. I can look more later, but if anyone has ideas here I'd appreciate it.

views/components/ObjectSidebarPane.js

@@ -1,20 +1,20 @@
 /**
  * Copyright (c) 2013, Facebook, 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 copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
- * 
+ *
  *  * Neither the name Facebook nor the names of its contributors may be used to
  *    endorse or promote products derived from this software without specific
  *    prior written permission.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -47,7 +47,7 @@ ReactPanel.ObjectSidebarPane.prototype = {
     var section = new WebInspector.ObjectPropertiesSection(object, '', '', this._emptyPlaceholder, false, null, ReactPanel.EditableObjectPropertyTreeElement.bind(null, this.onedit.bind(this)));
     section.expanded = true;
     section.editable = true;
-    section.headerElement.addStyleClass("hidden");
+    section.headerElement.classList.add("hidden");
     body.appendChild(section.element);
   },