Remove TabContents from TabStripModelObserver::ActiveTabChanged.

chrome/browser/ui/gtk/tabs/tab_strip_gtk.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/gtk/tabs/tab_strip_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 1029 matching lines @@
 
 void TabStripGtk::TabDetachedAt(WebContents* contents, int index) {
   GenerateIdealBounds();
   StartRemoveTabAnimation(index, contents);
   // Have to do this _after_ calling StartRemoveTabAnimation, so that any
   // previous remove is completed fully and index is valid in sync with the
   // model index.
   GetTabAt(index)->set_closing(true);
 }
 
-void TabStripGtk::ActiveTabChanged(TabContents* old_contents,
-                                   TabContents* new_contents,
+void TabStripGtk::ActiveTabChanged(WebContents* old_contents,
+                                   WebContents* new_contents,
                                    int index,
                                    bool user_gesture) {
   TRACE_EVENT0("ui::gtk", "TabStripGtk::ActiveTabChanged");
   ReStack();
 }
 
 void TabStripGtk::TabSelectionChanged(TabStripModel* tab_strip_model,
                                       const TabStripSelectionModel& old_model) {
   // We have "tiny tabs" if the tabs are so tiny that the unselected ones are
   // a different size to the selected ones.
@@ skipping 1204 matching lines @@
 
 void TabStripGtk::SetNewTabButtonBackground() {
   SkColor color = theme_service_->GetColor(
       ThemeService::COLOR_BUTTON_BACKGROUND);
   SkBitmap background = theme_service_->GetImageNamed(
       IDR_THEME_WINDOW_CONTROL_BACKGROUND).AsBitmap();
   SkBitmap mask = theme_service_->GetImageNamed(
       IDR_NEWTAB_BUTTON_MASK).AsBitmap();
   newtab_button_->SetBackground(color, background, mask);
 }