Fix remaining warnings for -Wmissing-braces and enable on win clang.

chrome/installer/gcapi/gcapi.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.
 
 // NOTE: This code is a legacy utility API for partners to check whether
 //       Chrome can be installed and launched. Recent updates are being made
 //       to add new functionality. These updates use code from Chromium, the old
 //       coded against the win32 api directly. If you have an itch to shave a
 //       yak, feel free to re-write the old code too.
 
@@ skipping 238 matching lines @@
   // For XP itself, we only support SP2 and above.
   return ((version_info.dwMinorVersion > 1) ||
           (version_info.wServicePackMajor >= 2)) ?
       VERSION_XP_SP2_UP_TO_VISTA : VERSION_BELOW_XP_SP2;
 }
 
 // Note this function should not be called on old Windows versions where these
 // Windows API are not available. We always invoke this function after checking
 // that current OS is Vista or later.
 bool VerifyAdminGroup() {
-  SID_IDENTIFIER_AUTHORITY NtAuthority = SECURITY_NT_AUTHORITY;
+  SID_IDENTIFIER_AUTHORITY NtAuthority = {SECURITY_NT_AUTHORITY};
   PSID Group;
   BOOL check = ::AllocateAndInitializeSid(&NtAuthority, 2,
                                           SECURITY_BUILTIN_DOMAIN_RID,
                                           DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0,
                                           0, 0, 0,
                                           &Group);
   if (check) {
     if (!::CheckTokenMembership(NULL, Group, &check))
       check = FALSE;
   }
@@ skipping 519 matching lines @@
       key.WriteValue(kRelaunchAllowedAfterValue,
                      FormatDateOffsetByMonths(6)) != ERROR_SUCCESS ||
       !SetRelaunchExperimentLabels(relaunch_brandcode, shell_mode)) {
     if (error_code)
       *error_code = RELAUNCH_ERROR_RELAUNCH_FAILED;
     return FALSE;
   }
 
   return TRUE;
 }