Allow dynamic switching in and out of sidetabs mode.

chrome/browser/views/tabs/tab_strip.h

Index: chrome/browser/views/tabs/tab_strip.h
===================================================================
--- chrome/browser/views/tabs/tab_strip.h	(revision 41630)
+++ chrome/browser/views/tabs/tab_strip.h	(working copy)
@@ -74,6 +74,11 @@
   // Compatible tab strips can transfer tabs during drag and drop.
   bool IsCompatibleWith(TabStrip* other) const;
 
+  // Populates the BaseTabStrip implementation from its model. This is primarily
+  // useful when switching between display types and there are existing tabs.
+  // Upon initial creation the TabStrip is empty.
+  void InitFromModel();
+
   // BaseTabStrip implementation:
   virtual int GetPreferredHeight();
   virtual void SetBackgroundOffset(const gfx::Point& offset);
@@ -136,6 +141,8 @@
   virtual void CloseTab(Tab* tab);
   virtual bool IsCommandEnabledForTab(
       TabStripModel::ContextMenuCommand command_id, const Tab* tab) const;
+  virtual bool IsCommandCheckedForTab(
+      TabStripModel::ContextMenuCommand command_id, const Tab* tab) const;
   virtual void ExecuteCommandForTab(
       TabStripModel::ContextMenuCommand command_id, Tab* tab);
   virtual void StartHighlightTabsForCommand(