Changes semantics of TabSelectedAt. For multi-selection the TabStrip

chrome/browser/tabs/tab_strip_model_observer.h

 // Copyright (c) 2010 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_TABS_TAB_STRIP_MODEL_OBSERVER_H_
 #define CHROME_BROWSER_TABS_TAB_STRIP_MODEL_OBSERVER_H_
 #pragma once
 
 class TabContentsWrapper;
 class TabStripModel;
@@ skipping 43 matching lines @@
   // The specified TabContents at |index| is being detached, perhaps to be
   // inserted in another TabStripModel. The implementer should take whatever
   // action is necessary to deal with the TabContents no longer being present.
   virtual void TabDetachedAt(TabContentsWrapper* contents, int index);
 
   // The selected TabContents is about to change from |old_contents|.
   // This gives observers a chance to prepare for an impending switch before it
   // happens.
   virtual void TabDeselected(TabContentsWrapper* contents);
 
+  // Invoked any time the selection may have changed. |old_contents| identifies
+  // the previously selected contents. It is entirely possible for the newly
+  // selected tab contents to match |old_contents|. |user_gesture| specifies
+  // whether or not this was done by a user input event (e.g. clicking on a tab,
+  // keystroke) or as a side-effect of some other function.
+  //
+  // This implementation invokes |TabSelectedAt| only if the new and old
+  // contents differ. If you only care about when the selected contents changes,
+  // override |TabSelectedAt|.
+  virtual void TabSelectionChanged(TabStripModel* model,
+                                   TabContentsWrapper* old_contents,
+                                   bool user_gesture);
+
   // The selected TabContents changed from |old_contents| to |new_contents| at
   // |index|. |user_gesture| specifies whether or not this was done by a user
   // input event (e.g. clicking on a tab, keystroke) or as a side-effect of
   // some other function.
+  //
+  // NOTE: this is only invoked when the selected tab contents changes, if you
+  // care about all changes to the selection, override |TabSelectionChanged|
+  // instead.
   virtual void TabSelectedAt(TabContentsWrapper* old_contents,
                              TabContentsWrapper* new_contents,
                              int index,
                              bool user_gesture);
 
   // The specified TabContents at |from_index| was moved to |to_index|.
   virtual void TabMoved(TabContentsWrapper* contents,
                         int from_index,
                         int to_index);
 
@@ skipping 35 matching lines @@
 
   // Sent when the tabstrip model is about to be deleted and any reference held
   // must be dropped.
   virtual void TabStripModelDeleted();
 
  protected:
   virtual ~TabStripModelObserver() {}
 };
 
 #endif  // CHROME_BROWSER_TABS_TAB_STRIP_MODEL_OBSERVER_H_