Support DirectWrite with sandbox on

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 553 matching lines @@
 }
 
 bool InitTargetServices(sandbox::TargetServices* target_services) {
   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 don't not currently
+  // attempt to support Vista, where SP2 and the Platform Update are required.
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  return command_line.HasSwitch(switches::kEnableDirectWrite) &&
+         base::win::GetVersion() >= base::win::VERSION_WIN7;
+}
+
 base::ProcessHandle StartSandboxedProcess(
     SandboxedProcessLauncherDelegate* delegate,
     CommandLine* cmd_line) {
   const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
   std::string type_str = cmd_line->GetSwitchValueASCII(switches::kProcessType);
 
   TRACE_EVENT_BEGIN_ETW("StartProcessWithAccess", 0, type_str);
 
   bool in_sandbox = true;
   if (delegate)
@@ skipping 51 matching lines @@
     delegate->PreSandbox(&disable_default_policy, &exposed_dir);
 
   if (!disable_default_policy && !AddPolicyForSandboxedProcess(policy))
     return 0;
 
   if (type_str != switches::kRendererProcess) {
     // Hack for Google Desktop crash. Trick GD into not injecting its DLL into
     // this subprocess. See
     // http://code.google.com/p/chromium/issues/detail?id=25580
     cmd_line->AppendSwitchASCII("ignored", " --type=renderer ");
+  } else if (ShouldUseDirectWrite()) {

[jam, 2014/03/25 22:57:26]

nit: it would be clearer to have if (type_str == renderer) {} else {} instead of
this 

[scottmg, 2014/03/25 23:38:18]

Done.

+    AddDirectory(base::DIR_WINDOWS_FONTS,
+                 NULL,
+                 true,
+                 sandbox::TargetPolicy::FILES_ALLOW_READONLY,
+                 policy);
+    // We do not automatically propagate this from the browser command line,
+    // and instead only add it when we're actually setting up the sandbox to
+    // work with DirectWrite.
+    cmd_line->AppendSwitch(switches::kEnableDirectWrite);
   }
 
   sandbox::ResultCode result;
   if (!exposed_dir.empty()) {
     result = policy->AddRule(sandbox::TargetPolicy::SUBSYS_FILES,
                              sandbox::TargetPolicy::FILES_ALLOW_ANY,
                              exposed_dir.value().c_str());
     if (result != sandbox::SBOX_ALL_OK)
       return 0;
 
@@ skipping 89 matching lines @@
   }
 
   return false;
 }
 
 bool BrokerAddTargetPeer(HANDLE peer_process) {
   return g_broker_services->AddTargetPeer(peer_process) == sandbox::SBOX_ALL_OK;
 }
 
 }  // namespace content