Fix a few warnings that -Wnull-conversion of a future clang will complain about.

chrome/common/mac/mock_launchd.cc

 // Copyright (c) 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.
 
 #include "chrome/common/mac/mock_launchd.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ skipping 196 matching lines @@
   signature.protocolFamily = PF_UNIX;
   signature.socketType = SOCK_STREAM;
   signature.protocol = 0;
   size_t unix_addr_len = offsetof(struct sockaddr_un,
                                   sun_path) + path_len + 1;
   base::mac::ScopedCFTypeRef<CFDataRef> address(
       CFDataCreate(NULL, reinterpret_cast<UInt8*>(&unix_addr), unix_addr_len));
   signature.address = address;
 
   CFSocketRef socket =
-      CFSocketCreateWithSocketSignature(NULL, &signature, NULL, NULL, NULL);
+      CFSocketCreateWithSocketSignature(NULL, &signature, 0, NULL, NULL);
 
   local_pipe = CFSocketGetNative(socket);
   EXPECT_NE(-1, local_pipe);
   if (local_pipe == -1) {
     if (error) {
       *error = CFErrorCreate(kCFAllocatorDefault, kCFErrorDomainPOSIX,
                              errno, NULL);
     }
     return NULL;
   }
@@ skipping 65 matching lines @@
                               Type type,
                               CFStringRef name) {
   delete_called_ = true;
   return true;
 }
 
 void MockLaunchd::SignalReady() {
   ASSERT_TRUE(as_service_);
   running_lock_.reset(TakeNamedLock(pipe_name_, true));
 }