Correct iOS build for latest Xcode beta.

ios/web/test/crw_fake_web_controller_observer.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/test/crw_fake_web_controller_observer.h"
 
 #import "base/logging.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/values.h"
 
 @implementation CRWFakeWebControllerObserver {
   ScopedVector<base::DictionaryValue> _commandsReceived;
   base::scoped_nsobject<NSString> _commandPrefix;
 }
 
 @synthesize pageLoaded = _pageLoaded;
 
-- (instancetype)init {
-  NOTREACHED();
-  return nil;
-}
-
 - (instancetype)initWithCommandPrefix:(NSString*)commandPrefix {
   DCHECK(commandPrefix);
   self = [super init];
   if (self) {
     _commandPrefix.reset([commandPrefix copy]);
   }
   return self;
 }
 
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
 - (void)pageLoaded:(CRWWebController*)webController {
   _pageLoaded = YES;
 }
 
 - (NSString*)commandPrefix {
   return _commandPrefix;
 }
 
 - (BOOL)handleCommand:(const base::DictionaryValue&)command
         webController:(CRWWebController*)webController
     userIsInteracting:(BOOL)userIsInteracting
             originURL:(const GURL&)originURL {
   _commandsReceived.push_back(command.DeepCopy());
   return YES;
 }
 
 - (ScopedVector<base::DictionaryValue>&)commandsReceived {
   return _commandsReceived;
 }
 
 @end