Correct iOS build for latest Xcode beta.

ios/chrome/browser/xcallback_parameters.mm

 // Copyright 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 "ios/chrome/browser/xcallback_parameters.h"
 
+#include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 
 namespace {
 NSString* const kSourceAppIdKey = @"sourceAppId";
 NSString* const kSourceAppNameKey = @"sourceAppName";
 NSString* const kSuccessURLKey = @"successURL";
 NSString* const kCreateNewTabKey = @"createNewTab";
 }
 
@@ skipping 17 matching lines @@
   self = [super init];
   if (self) {
     _sourceAppId.reset([sourceAppId copy]);
     _sourceAppName.reset([sourceAppName copy]);
     _successURL = successURL;
     _createNewTab = createNewTab;
   }
   return self;
 }
 
+- (instancetype)init {
+  NOTREACHED();
+  return nil;
+}
+
 - (NSString*)description {
   return [NSString stringWithFormat:@"SourceApp: %@ (%@)\nSuccessURL: %s\n",
                                     _sourceAppName.get(), _sourceAppId.get(),
                                     _successURL.spec().c_str()];
 }
 
 - (NSString*)sourceAppId {
   return _sourceAppId.get();
 }
 
@@ skipping 31 matching lines @@
 - (instancetype)copyWithZone:(NSZone*)zone {
   XCallbackParameters* copy = [[[self class] allocWithZone:zone] init];
   copy->_sourceAppId.reset([_sourceAppId copy]);
   copy->_sourceAppName.reset([_sourceAppName copy]);
   copy->_successURL = _successURL;
   copy->_createNewTab = _createNewTab;
   return copy;
 }
 
 @end