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

net/base/x509_util_mac.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 "net/base/x509_util_mac.h"
 
 #include "base/logging.h"
 #include "third_party/apple_apsl/cssmapplePriv.h"
 
 namespace net {
@@ skipping 115 matching lines @@
     if (status)
       return status;
     CFArrayAppendValue(policies, crl_policy);
     CFRelease(crl_policy);
   }
 
   return status;
 }
 
 CSSMFieldValue::CSSMFieldValue()
-    : cl_handle_(NULL),
+    : cl_handle_(CSSM_INVALID_HANDLE),
       oid_(NULL),
       field_(NULL) {
 }
 CSSMFieldValue::CSSMFieldValue(CSSM_CL_HANDLE cl_handle,
                                const CSSM_OID* oid,
                                CSSM_DATA_PTR field)
     : cl_handle_(cl_handle),
       oid_(const_cast<CSSM_OID_PTR>(oid)),
       field_(field) {
 }
 
 CSSMFieldValue::~CSSMFieldValue() {
-  Reset(NULL, NULL, NULL);
+  Reset(CSSM_INVALID_HANDLE, NULL, NULL);
 }
 
 void CSSMFieldValue::Reset(CSSM_CL_HANDLE cl_handle,
                            CSSM_OID_PTR oid,
                            CSSM_DATA_PTR field) {
   if (cl_handle_ && oid_ && field_)
     CSSM_CL_FreeFieldValue(cl_handle_, oid_, field_);
   cl_handle_ = cl_handle;
   oid_ = oid;
   field_ = field;
 }
 
 CSSMCachedCertificate::CSSMCachedCertificate()
-    : cl_handle_(NULL),
-      cached_cert_handle_(NULL) {
+    : cl_handle_(CSSM_INVALID_HANDLE),
+      cached_cert_handle_(CSSM_INVALID_HANDLE) {
 }
 CSSMCachedCertificate::~CSSMCachedCertificate() {
   if (cl_handle_ && cached_cert_handle_)
     CSSM_CL_CertAbortCache(cl_handle_, cached_cert_handle_);
 }
 
 OSStatus CSSMCachedCertificate::Init(SecCertificateRef os_cert_handle) {
   DCHECK(!cl_handle_ && !cached_cert_handle_);
   DCHECK(os_cert_handle);
   CSSM_DATA cert_data;
@@ skipping 12 matching lines @@
   return status;
 }
 
 OSStatus CSSMCachedCertificate::GetField(const CSSM_OID* field_oid,
                                          CSSMFieldValue* field) const {
   DCHECK(cl_handle_);
   DCHECK(cached_cert_handle_);
 
   CSSM_OID_PTR oid = const_cast<CSSM_OID_PTR>(field_oid);
   CSSM_DATA_PTR field_ptr = NULL;
-  CSSM_HANDLE results_handle = NULL;
+  CSSM_HANDLE results_handle = CSSM_INVALID_HANDLE;
   uint32 field_value_count = 0;
   CSSM_RETURN status = CSSM_CL_CertGetFirstCachedFieldValue(
       cl_handle_, cached_cert_handle_, oid, &results_handle,
       &field_value_count, &field_ptr);
   if (status)
     return status;
 
   // Note: |field_value_count| may be > 1, indicating that more than one
   // value is present. This may happen with extensions, but for current
   // usages, only the first value is returned.
   CSSM_CL_CertAbortQuery(cl_handle_, results_handle);
   field->Reset(cl_handle_, oid, field_ptr);
   return CSSM_OK;
 }
 
 }  // namespace x509_util
 
 }  // namespace net