Move most of the remaining users of WebContentsObserver::tab_contents() to use web_contents().

chrome/browser/ui/alternate_error_tab_observer.h

Index: chrome/browser/ui/alternate_error_tab_observer.h
===================================================================
--- chrome/browser/ui/alternate_error_tab_observer.h	(revision 115777)
+++ chrome/browser/ui/alternate_error_tab_observer.h	(working copy)
@@ -10,18 +10,21 @@
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 
-class TabContentsWrapper;
+class Profile;
 
 // Per-tab class to implement alternate error page functionality.
 class AlternateErrorPageTabObserver : public content::WebContentsObserver,
                                       public content::NotificationObserver {
  public:
-  explicit AlternateErrorPageTabObserver(TabContentsWrapper* wrapper);
+  explicit AlternateErrorPageTabObserver(content::WebContents* web_contents);
   virtual ~AlternateErrorPageTabObserver();
 
   static void RegisterUserPrefs(PrefService* prefs);
 
  private:
+  // Helper to return the profile for this tab.
+  Profile* GetProfile() const;
+
   // content::WebContentsObserver overrides:
   virtual void RenderViewCreated(RenderViewHost* render_view_host) OVERRIDE;
 
@@ -39,9 +42,6 @@
   // Send the alternate error page URL to the renderer.
   void UpdateAlternateErrorPageURL(RenderViewHost* rvh);
 
-  // Our owning TabContentsWrapper.
-  TabContentsWrapper* wrapper_;
-
   content::NotificationRegistrar registrar_;
   PrefChangeRegistrar pref_change_registrar_;