Move extensions bindings code out of //chrome

extensions/renderer/document_custom_bindings.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_RENDERER_EXTENSIONS_DOCUMENT_CUSTOM_BINDINGS_H_
-#define CHROME_RENDERER_EXTENSIONS_DOCUMENT_CUSTOM_BINDINGS_H_
+#ifndef EXTENSIONS_RENDERER_DOCUMENT_CUSTOM_BINDINGS_H_
+#define EXTENSIONS_RENDERER_DOCUMENT_CUSTOM_BINDINGS_H_
 
-#include "chrome/renderer/extensions/chrome_v8_extension.h"
+#include "extensions/renderer/object_backed_native_handler.h"
 
 namespace extensions {
+class ScriptContext;
 
 // Implements custom bindings for document-level operations.
-class DocumentCustomBindings : public ChromeV8Extension {
+class DocumentCustomBindings : public ObjectBackedNativeHandler {
  public:
-  DocumentCustomBindings(Dispatcher* dispatcher, ChromeV8Context* context);
+  DocumentCustomBindings(ScriptContext* context);
 
  private:
   // Registers the provided element as a custom element in Blink.
   void RegisterElement(const v8::FunctionCallbackInfo<v8::Value>& args);
 };
 
 }  // namespace extensions
 
-#endif  // CHROME_RENDERER_EXTENSIONS_DOCUMENT_CUSTOM_BINDINGS_H_
+#endif  // EXTENSIONS_RENDERER_DOCUMENT_CUSTOM_BINDINGS_H_