Allow dynamic switching in and out of sidetabs mode.

chrome/browser/views/frame/browser_view.h

Index: chrome/browser/views/frame/browser_view.h
===================================================================
--- chrome/browser/views/frame/browser_view.h	(revision 41630)
+++ chrome/browser/views/frame/browser_view.h	(working copy)
@@ -151,7 +151,7 @@
   bool IsTabStripVisible() const;
 
   // Returns true if the vertical tabstrip is in use.
-  bool UsingSideTabs() const;
+  bool UseVerticalTabs() const;
 
   // Returns true if the profile associated with this Browser window is
   // off the record.
@@ -322,6 +322,7 @@
   virtual void Cut();
   virtual void Copy();
   virtual void Paste();
+  virtual void ToggleTabStripMode();
 
   // Overridden from BrowserWindowTesting:
   virtual BookmarkBarView* GetBookmarkBarView() const;
@@ -397,9 +398,10 @@
   // override to implemnet different layout pocily.
   virtual views::LayoutManager* CreateLayoutManager() const;
 
-  // Returns a new TabStrip for the browser view. A subclass may
-  // override to return a different TabStrip implementation.
-  virtual BaseTabStrip* CreateTabStrip(TabStripModel* tab_strip_model);
+  // Initializes a new TabStrip for the browser view. This can be performed
+  // multiple times over the life of the browser, and is run when the display
+  // mode for the tabstrip changes from horizontal to vertical.
+  void InitTabStrip(TabStripModel* tab_strip_model);
 
   // Browser window related initializations.
   virtual void Init();