Update comments for AuthorizationExecuteWithPrivileges.

chrome/installer/mac/app/AuthorizedInstall.m

 // Copyright 2016 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 "AuthorizedInstall.h"
 
 @interface AuthorizedInstall () {
   NSFileHandle* communicationFile_;
   NSString* destinationAppBundlePath_;
 }
@@ skipping 17 matching lines @@
 
 // Starts up the proccess with privileged permissions.
 - (void)startPrivilegedTool:(const char*)toolPath
               withArguments:(const char**)args
               authorization:(AuthorizationRef)authRef
                      status:(OSStatus)status {
   if (status != errAuthorizationSuccess)
     return;
 
   FILE* file;
+// AuthorizationExecuteWithPrivileges is deprecated in macOS 10.7, but no good
+// replacement exists. https://crbug.com/593133.
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
   status = AuthorizationExecuteWithPrivileges(
       authRef, toolPath, kAuthorizationFlagDefaults, (char* const*)args, &file);
 #pragma clang diagnostic pop
   communicationFile_ = [[NSFileHandle alloc] initWithFileDescriptor:fileno(file)
                                                      closeOnDealloc:YES];
 }
 
 // Starts up same proccess as above without privileged permissions.
@@ skipping 72 matching lines @@
   [communicationFile_  writeData:[[message stringByAppendingString:@"\n"]
                dataUsingEncoding:NSUTF8StringEncoding]];
 }
 
 - (NSString*)startInstall:(NSString*)appBundlePath {
   [self sendMessageToTool:appBundlePath];
   return destinationAppBundlePath_;
 }
 
 @end