Remove TabContents from AddBlankTabAt, kill AddBlankTab.

chrome/browser/ui/tabs/tab_strip_model.h

Index: chrome/browser/ui/tabs/tab_strip_model.h
diff --git a/chrome/browser/ui/tabs/tab_strip_model.h b/chrome/browser/ui/tabs/tab_strip_model.h
index 22cef25fb388c7bdf5cdf490454851e843c3e8e0..fe8002fe4c1e25bda1994e860f17318f9f2327e8 100644
--- a/chrome/browser/ui/tabs/tab_strip_model.h
+++ b/chrome/browser/ui/tabs/tab_strip_model.h
@@ -414,7 +414,8 @@ class TabStripModel : public content::NotificationObserver {
   // Adds a TabContents at the best position in the TabStripModel given
   // the specified insertion index, transition, etc. |add_types| is a bitmask of
   // AddTabTypes; see it for details. This method ends up calling into
-  // InsertTabContentsAt to do the actual insertion.
+  // InsertTabContentsAt to do the actual insertion. Pass -1 for |index| to
+  // append the contents to the end of the tab strip.
   void AddTabContents(TabContents* contents,
                       int index,
                       content::PageTransition transition,