Fix crash when using Instant.

chrome/browser/ui/cocoa/tabs/tab_strip_controller_unittest.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include <vector>
 
 #include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/browser/ui/browser_window.h"
@@ skipping 22 matching lines @@
 @implementation TestTabStripControllerDelegate
 - (void)onActivateTabWithContents:(WebContents*)contents {
 }
 - (void)onReplaceTabWithContents:(WebContents*)contents {
 }
 - (void)onTabChanged:(TabStripModelObserver::TabChangeType)change
         withContents:(WebContents*)contents {
 }
 - (void)onTabDetachedWithContents:(WebContents*)contents {
 }
+- (void)onInsertTabWithContents:(WebContents*)contents {
+}
 @end
 
 @interface TabStripController (Test)
 
 - (void)mouseMoved:(NSEvent*)event;
 
 @end
 
 @implementation TabView (Test)
 
@@ skipping 168 matching lines @@
 
   [controller_.get() mouseMoved:event];
   EXPECT_STREQ("Tab2",
       [[controller_ view:nil
         stringForToolTip:nil
                    point:NSMakePoint(0,0)
                 userData:nil] cStringUsingEncoding:NSASCIIStringEncoding]);
 }
 
 }  // namespace