Add an extension bubble explaining which extensions are in dev mode.

chrome/browser/extensions/suspicious_extension_bubble.h

-// Copyright (c) 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_BROWSER_EXTENSIONS_SUSPICIOUS_EXTENSION_BUBBLE_H_
-#define CHROME_BROWSER_EXTENSIONS_SUSPICIOUS_EXTENSION_BUBBLE_H_
-
-#include "base/bind.h"
-
-class Browser;
-
-namespace extensions {
-
-// The interface between the SuspiciousExtensionBubble bubble and its
-// controller.
-class SuspiciousExtensionBubble {
- public:
-  // Setup the callback for when the button is clicked in the bubble.
-  virtual void OnButtonClicked(const base::Closure& callback) = 0;
-  // Setup the callback for when the link is clicked in the bubble.
-  virtual void OnLinkClicked(const base::Closure&) = 0;
-  // Instruct the bubble to appear.
-  virtual void Show() = 0;
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_SUSPICIOUS_EXTENSION_BUBBLE_H_