Fix regression with back-button not working on prerendered and instant pages.

content/browser/tab_contents/tab_contents.h

Index: content/browser/tab_contents/tab_contents.h
diff --git a/content/browser/tab_contents/tab_contents.h b/content/browser/tab_contents/tab_contents.h
index f7b71c5e4f2cc6cd4cd23b6e4008d12af1108e21..0a7403a2897691f27483ea3c82f1884c8d6eb55c 100644
--- a/content/browser/tab_contents/tab_contents.h
+++ b/content/browser/tab_contents/tab_contents.h
@@ -623,6 +623,13 @@ class TabContents : public PageNavigator,
   bool NavigateToEntry(const NavigationEntry& entry,
                        NavigationController::ReloadType reload_type);
 
+  // Sets the history for this tab_contents to |history_length| entries, and

[Charlie Reis, 2011/08/09 20:59:31]

Sounds odd to me to "set the history for a TabContents."  History is maintained
in the NavigationController and not here, but NavigationController is the one
telling us to do this.

Perhaps we should say that it updates the history length in the current
RenderView.

[Charlie Reis, 2011/08/09 23:25:16]

Can you squeeze in this fix as well?

+  // moves the current page_id to the last entry in the list if it's valid.
+  // This is mainly used when a prerendered page is swapped into the current
+  // tab.
+  void SetHistoryLengthAndClear(int history_length);
+
+
   // Misc non-view stuff -------------------------------------------------------
 
   // Helper functions for sending notifications.