Convert ios_web_view_shell to pure Objective-C.

ios/web_view/shell/shell_app_delegate.mm

-// Copyright 2014 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 "ios/web_view/shell/shell_app_delegate.h"
-
-#import "ios/web_view/public/criwv.h"
-#import "ios/web_view/shell/shell_delegate.h"
-#import "ios/web_view/shell/shell_view_controller.h"
-
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
-
-@interface ShellAppDelegate ()
-@property (nonatomic, strong) ShellDelegate* delegate;
-@end
-
-@implementation ShellAppDelegate
-
-@synthesize delegate = _delegate;
-@synthesize window = _window;
-
-- (BOOL)application:(UIApplication*)application
-    didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
-  self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
-  self.window.backgroundColor = [UIColor whiteColor];
-
-  self.delegate = [[ShellDelegate alloc] init];
-  [CRIWV configureWithDelegate:_delegate];
-
-  [self.window makeKeyAndVisible];
-
-  ShellViewController* controller = [[ShellViewController alloc] init];
-  self.window.rootViewController = controller;
-
-  return YES;
-}
-
-- (void)applicationWillResignActive:(UIApplication*)application {
-}
-
-- (void)applicationDidEnterBackground:(UIApplication*)application {
-}
-
-- (void)applicationWillEnterForeground:(UIApplication*)application {
-}
-
-- (void)applicationDidBecomeActive:(UIApplication*)application {
-}
-
-- (void)applicationWillTerminate:(UIApplication*)application {
-  [CRIWV shutDown];
-}
-
-@end