Don't expose document.register to Chrome Apps by default.

chrome/renderer/extensions/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_
+
+#include "chrome/renderer/extensions/chrome_v8_extension.h"
+
+namespace extensions {
+
+// Implements custom bindings for document-level operations.
+class DocumentCustomBindings : public ChromeV8Extension {
+ public:
+  DocumentCustomBindings(Dispatcher* dispatcher, ChromeV8Context* 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_