Correct iOS build for latest Xcode beta.

ios/web/crw_browsing_data_store_unittest.mm

 // Copyright 2015 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/public/crw_browsing_data_store.h"
 
 #include "base/ios/ios_util.h"
 #include "base/logging.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #import "base/test/ios/wait_util.h"
 #include "ios/web/public/active_state_manager.h"
 #include "ios/web/public/browser_state.h"
 #include "ios/web/public/test/test_browser_state.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
 // An observer to observe the |mode| key changes to a CRWBrowsingDataStore.
 // Used for testing purposes.
 @interface CRWTestBrowsingDataStoreObserver : NSObject
+- (instancetype)init UNAVAILABLE_ATTRIBUTE;

[droger, 2015/06/10 15:59:10]

NS_UNAVAILABLE

[justincohen, 2015/06/10 16:02:25]

Done.

 // Designated init. |browsingDataStore| cannot be null.
 - (instancetype)initWithBrowsingDataStore:
         (CRWBrowsingDataStore*)browsingDataStore NS_DESIGNATED_INITIALIZER;
 // The number of times that the mode of the underlying CRWBrowsingDataStore
 // changed.
 @property(nonatomic, assign) NSUInteger modeChangeCount;
 @end
 
 @implementation CRWTestBrowsingDataStoreObserver {
   // The underlying CRWBrowsingDataStore.
   __weak CRWBrowsingDataStore* _browsingDataStore;
 }
 
 @synthesize modeChangeCount = _modeChangeCount;
 
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
 - (instancetype)initWithBrowsingDataStore:
         (CRWBrowsingDataStore*)browsingDataStore {
   self = [super init];
   if (self) {
     DCHECK(browsingDataStore);
     [browsingDataStore addObserver:self
                         forKeyPath:@"mode"
                            options:0
                            context:nil];
     _browsingDataStore = browsingDataStore;
@@ skipping 184 matching lines @@
 
   ASSERT_EQ(ACTIVE, [browsing_data_store_ mode]);
 
   [browsing_data_store_ makeInactiveWithCompletionHandler:nil];
   // |removeDataOfTypes| is called immediately after a |makeInactive| call.
   RemoveDataOfTypes(BROWSING_DATA_TYPE_COOKIES);
   EXPECT_EQ(INACTIVE, [browsing_data_store_ mode]);
 }
 
 }  // namespace web