Add Android's context menu handler used on the NTP.

chrome/browser/ui/webui/ntp/android/context_menu_handler.h

+// Copyright (c) 2012 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_BROWSER_UI_WEBUI_NTP_ANDROID_CONTEXT_MENU_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_NTP_ANDROID_CONTEXT_MENU_HANDLER_H_
+
+#include "base/memory/ref_counted.h"
+#include "content/public/browser/web_ui_message_handler.h"
+
+namespace base {
+class ListValue;
+}
+
+class OnContextMenuItemSelectedCallBack;
+
+// The handler for Javascript messages related to the context menus.

[Evan Stade, 2012/08/22 00:24:51]

nit: JavaScript

[Ted C, 2012/08/22 20:55:50]

Done.

+// Its the job of the actual HTML page to intercept the contextmenu event,

[Evan Stade, 2012/08/22 00:24:51]

nit: It's

[Ted C, 2012/08/22 20:55:50]

Done.

+// disable it and show its own custom menu.
+class ContextMenuHandler : public content::WebUIMessageHandler {
+ public:
+  ContextMenuHandler();
+  virtual ~ContextMenuHandler();
+
+  // WebUIMessageHandler override and implementation.
+  virtual void RegisterMessages() OVERRIDE;
+
+  // Invoked (by on_item_selected_callback_) when an item has been selected.
+  void OnItemSelected(int item_id);
+
+  // Callback for the "showContextMenu" message.
+  void HandleShowContextMenu(const base::ListValue* args);
+
+  // Below are the message that are so far only triggered by the context menu.
+  // They should be moved to other files if they become used from other places.
+
+  // Callback for the "openInNewTab" message.
+  void HandleOpenInNewTab(const base::ListValue* args);
+
+  // Callback for the "openInIncognitoTab" message.
+  void HandleOpenInIncognitoTab(const base::ListValue* args);
+
+  // Called by the OnContextMenuItemSelectedCallBack.
+  void SetOnItemSelectedCallback(OnContextMenuItemSelectedCallBack* callback);
+
+ private:
+  // Clears our reference to the callback and clears the callback's reference to
+  // us.
+  void ReleaseCallback();
+
+  // The callback invoked when an item is selected. That callback might outlive
+  // us, so we make sure to clear the reference the callback has to us when
+  // we are destroyed.
+  scoped_refptr<OnContextMenuItemSelectedCallBack> on_item_selected_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContextMenuHandler);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_NTP_ANDROID_CONTEXT_MENU_HANDLER_H_