Web Intents Mac: Add view animation

chrome/browser/ui/cocoa/intents/web_intent_extension_prompt_view_controller.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 "chrome/browser/ui/cocoa/intents/web_intent_extension_prompt_view_controller.h"
 
 #include <cmath>
 
 #import "chrome/browser/ui/cocoa/extensions/extension_install_view_controller.h"
 #import "chrome/browser/ui/cocoa/flipped_view.h"
@@ skipping 15 matching lines @@
   if (viewController_.get())
     return;
 
   viewController_.reset([[ExtensionInstallViewController alloc]
       initWithNavigator:navigator
                delegate:delegate
                  prompt:prompt]);
   [[self view] addSubview:[viewController_ view]];
 }
 
-- (void)clear {
-  [[viewController_ view] removeFromSuperview];
-  viewController_.reset();
-}
-
 - (ExtensionInstallViewController*)viewController {
   return viewController_;
 }
 
 - (void)sizeToFitAndLayout {
   if (!viewController_) {
     [[self view] setFrameSize:NSZeroSize];
     return;
   }
 
   NSSize size = [[viewController_ view] bounds].size;
   [[self view] setFrameSize:size];
   [[viewController_ view] setFrameOrigin:NSZeroPoint];
 }
 
+- (void)viewRemovedFromSuperview {
+  [[viewController_ view] removeFromSuperview];
+  viewController_.reset();
+}
+
 @end