Add pin icon to the omnibar in windows 8 metro mode.

chrome/browser/ui/metro_pin_tab_helper.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_METRO_PIN_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_METRO_PIN_TAB_HELPER_H_
 
 #include "content/public/browser/web_contents_observer.h"
 
 // Per-tab class to help manage metro pinning.
 class MetroPinTabHelper : public content::WebContentsObserver {
  public:
-  explicit MetroPinTabHelper(content::WebContents* tab_contents);
+  // Objects implement this interface to get notified about changes in the
+  // metro pinned state.
+  class Delegate {

[sky, 2012/07/20 16:46:41]

Move this into its own file.

[benwells, 2012/07/23 08:03:43]

Done.

+   public:
+    // Notification that the pinned state of the current URL changed.
+    virtual void IsPinnedChanged(content::WebContents* source, bool pinned) = 0;
+
+   protected:
+    virtual ~Delegate();
+  };
+  explicit MetroPinTabHelper(content::WebContents* web_contents);
   virtual ~MetroPinTabHelper();
 
   bool is_pinned() const { return is_pinned_; }
 
+  void set_delegate(Delegate* delegate) { delegate_ = delegate; }
+
   void TogglePinnedToStartScreen();
 
   // content::WebContentsObserver overrides:
   virtual void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
 
  private:
   // Queries the metro driver about the pinned state of the current URL.
   void UpdatePinnedStateForCurrentURL();
 
+  // Update the pinned state and notify the delegate.
+  void SetIsPinned(bool is_pinned);
+
   // Whether the current URL is pinned to the metro start screen.
   bool is_pinned_;
 
+  // The delegate that we inform when the is_pinned_ state changes.
+  Delegate* delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(MetroPinTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_METRO_PIN_TAB_HELPER_H_