Add Observer in FaviconTabHelper

chrome/browser/favicon/favicon_tab_helper_observer.h

Index: chrome/browser/favicon/favicon_tab_helper_observer.h
diff --git a/chrome/browser/favicon/favicon_tab_helper_observer.h b/chrome/browser/favicon/favicon_tab_helper_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..40c0e6efe0b231749c7f22c5b3ba211646753c2f
--- /dev/null
+++ b/chrome/browser/favicon/favicon_tab_helper_observer.h
@@ -0,0 +1,24 @@
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.

[sky, 2014/11/04 21:06:31]

style guide says no more (c).

[michaelbai, 2014/11/04 21:51:27]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_OBSERVER_H_
+#define CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_OBSERVER_H_
+
+namespace gfx {
+class Image;
+}
+
+// An observer implemented by classes which are interested in envent in
+// FaviconTabHelper.
+class FaviconTabHelperObserver {
+ public:
+  // Called when favicon |image| is retrieved from either web site or history
+  // backend.
+  virtual void OnFaviconAvailable(const gfx::Image& image) = 0;
+
+ protected:
+  virtual ~FaviconTabHelperObserver();

[sky, 2014/11/04 21:06:31]

You can inline the destructor and nuke the .cc.

[michaelbai, 2014/11/04 21:51:27]

Done.

+};
+
+#endif  // CHROME_BROWSER_FAVICON_FAVICON_TAB_HELPER_OBSERVER_H_