Remove TabContents from TabStripModelObserver::ActiveTabChanged.

chrome/browser/ui/tabs/tab_strip_model_observer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 
 using content::WebContents;
 
 void TabStripModelObserver::TabInsertedAt(WebContents* contents,
                                           int index,
                                           bool foreground) {
 }
 
 void TabStripModelObserver::TabClosingAt(TabStripModel* tab_strip_model,
                                          WebContents* contents,
                                          int index) {
 }
 
 void TabStripModelObserver::TabDetachedAt(WebContents* contents,
                                           int index) {
 }
 
 void TabStripModelObserver::TabDeactivated(WebContents* contents) {
 }
 
-void TabStripModelObserver::ActiveTabChanged(TabContents* old_contents,
-                                             TabContents* new_contents,
+void TabStripModelObserver::ActiveTabChanged(WebContents* old_contents,
+                                             WebContents* new_contents,
                                              int index,
                                              bool user_gesture) {
 }
 
 void TabStripModelObserver::TabSelectionChanged(
     TabStripModel* tab_strip_model,
     const TabStripSelectionModel& model) {
 }
 
 void TabStripModelObserver::TabMoved(TabContents* contents,
@@ skipping 20 matching lines @@
                                                 int index) {
 }
 
 void TabStripModelObserver::TabBlockedStateChanged(WebContents* contents,
                                                    int index) {
 }
 
 void TabStripModelObserver::TabStripEmpty() {}
 
 void TabStripModelObserver::TabStripModelDeleted() {}