Multi-tab: Adding new Notification when tab selection changes.

chrome/browser/tabs/tab_strip_model_observer.h

Index: chrome/browser/tabs/tab_strip_model_observer.h
diff --git a/chrome/browser/tabs/tab_strip_model_observer.h b/chrome/browser/tabs/tab_strip_model_observer.h
index 290d7700c87e506128313b0009e96ecee1c71663..da1e61d86bfb28f82ca6ac59a4d88bb81ad3fe56 100644
--- a/chrome/browser/tabs/tab_strip_model_observer.h
+++ b/chrome/browser/tabs/tab_strip_model_observer.h
@@ -8,6 +8,7 @@
 
 class TabContentsWrapper;
 class TabStripModel;
+class TabStripSelectionModel;
 
 ////////////////////////////////////////////////////////////////////////////////
 //
@@ -63,22 +64,18 @@ class TabStripModelObserver {
 
   // Sent when the selection changes. The previously selected tab is identified

[sky, 2011/06/03 15:35:56]

'Sent when the selection changes' -> 'Sent when the active tab changes'.

[dpapad, 2011/06/03 17:49:01]

Done.

   // by |old_contents| and the newly selected tab by |new_contents|. |index| is
-  // the index of |new_contents|. When using multiple selection this may be sent
-  // even when the active tab has not changed. For example, if the selection is
-  // extended this method is invoked to inform observers the selection has
-  // changed, but |old_contents| and |new_contents| are the same.  If you only
-  // care about when the active tab changes, check for when |old_contents|
-  // differs from |new_contents|. |user_gesture| specifies whether or not this
+  // the index of |new_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.

[sky, 2011/06/03 15:35:56]

Also add something about 'TabSelectionChanged'. Maybe:
Note: it is possible for the selection to change but not the active tab. For
example, control-click may not change the active tab but does change the
selection. In this case 'ActiveTabChanged' is not sent. If you care about any
changes to the selection, use TabSelectionChanged.

[dpapad, 2011/06/03 17:49:01]

Done.

-  //
-  // TODO(dpapad): Add TabSelectionChanged method for when the selected tabs
-  // change.
   virtual void ActiveTabChanged(TabContentsWrapper* old_contents,
                                 TabContentsWrapper* new_contents,
                                 int index,
                                 bool user_gesture);
 
+  // Sent when the selection changes. More precisely when selected tabs, anchor
+  // tab or active tab change.

[sky, 2011/06/03 15:35:56]

Add something about see also ActiveTabChanged for details.

[dpapad, 2011/06/03 17:49:01]

Done.

+  virtual void TabSelectionChanged(const TabStripSelectionModel& model);

[sky, 2011/06/03 15:35:56]

model -> old_model. And also document what it is.

[dpapad, 2011/06/03 17:49:01]

Done.

+
   // The specified TabContents at |from_index| was moved to |to_index|.
   virtual void TabMoved(TabContentsWrapper* contents,
                         int from_index,