[ObjC ARC] Converts parts of ios/web/webstate to ARC.

ios/web/web_state/web_controller_observer_bridge.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/web_state/web_controller_observer_bridge.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ios/web/public/web_state/crw_web_controller_observer.h"
 #include "ios/web/public/web_state/web_state.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 WebControllerObserverBridge::WebControllerObserverBridge(
     id<CRWWebControllerObserver> web_controller_observer,
     WebState* web_state,
     CRWWebController* web_controller)
     : WebStateObserver(web_state),
       web_controller_observer_(web_controller_observer),
       web_controller_(web_controller) {
   DCHECK(web_controller_observer_);
@@ skipping 28 matching lines @@
     const GURL& url,
     bool user_is_interacting) {
   DCHECK(!script_command_callback_prefix_.empty());
   return [web_controller_observer_ handleCommand:value
                                    webController:web_controller_
                                userIsInteracting:user_is_interacting
                                        originURL:url];
 }
 
 }  // namespace web