Disable DirectWrite for pre-release versions of Windows 7

content/common/sandbox_win.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 "content/common/sandbox_win.h"
 
 #include <string>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
@@ skipping 548 matching lines @@
   DCHECK(target_services);
   DCHECK(!g_target_services);
   sandbox::ResultCode result = target_services->Init();
   g_target_services = target_services;
   return sandbox::SBOX_ALL_OK == result;
 }
 
 bool ShouldUseDirectWrite() {
   // If the flag is currently on, and we're on Win7 or above, we enable
   // DirectWrite. Skia does not require the additions to DirectWrite in QFE
-  // 2670838, so a Win7 check is sufficient. We do not currently attempt to
-  // support Vista, where SP2 and the Platform Update are required.
+  // 2670838, but a simple 'better than XP' check is not enough.
   if (base::win::GetVersion() < base::win::VERSION_WIN7)
     return false;
 
+  base::win::OSInfo::VersionNumber os_version =
+      base::win::OSInfo::GetInstance()->version_number();
+  if ((os_version.major == 6) && (os_version.minor == 1)) {
+    // We can't use DirectWrite for pre-release versions of Windows 7.
+    if (os_version.build < 7600)
+      return false;
+  }
+
   // If forced off, don't use it.
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kDisableDirectWrite))
     return false;
 
 #if !defined(NACL_WIN64)
   // Can't use GDI on HiDPI.
   if (gfx::GetDPIScale() > 1.0f)
     return true;
 #endif
@@ skipping 182 matching lines @@
   }
 
   return false;
 }
 
 bool BrokerAddTargetPeer(HANDLE peer_process) {
   return g_broker_services->AddTargetPeer(peer_process) == sandbox::SBOX_ALL_OK;
 }
 
 }  // namespace content