Do not use win32k renderer lockdown if DirectWrite is disabled.

content/common/content_switches_internal.cc

Index: content/common/content_switches_internal.cc
diff --git a/content/common/content_switches_internal.cc b/content/common/content_switches_internal.cc
index 76d877224a4ef9d076cf8bfe0f0b7d498a18d57e..68b24c477078bce0bc060276cbf74758908a651d 100644
--- a/content/common/content_switches_internal.cc
+++ b/content/common/content_switches_internal.cc
@@ -5,10 +5,12 @@
 #include "content/common/content_switches_internal.h"
 
 #include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "content/public/common/content_switches.h"
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
+#include "ui/gfx/win/direct_write.h"
 #endif
 
 namespace content {
@@ -31,4 +33,23 @@ bool IsPinchToZoomEnabled() {
 #endif
 }
 
+#if defined(OS_WIN)
+
+bool IsWin32kRendererLockdownEnabled() {
+  const std::string group_name =
+      base::FieldTrialList::FindFullName("Win32kLockdown");
+  if (base::win::GetVersion() < base::win::VERSION_WIN8)
+    return false;
+  if (!gfx::win::ShouldUseDirectWrite())
+    return false;
+  const base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
+  if (cmd_line->HasSwitch(switches::kEnableWin32kRendererLockDown))
+    return true;
+  if (cmd_line->HasSwitch(switches::kDisableWin32kRendererLockDown))
+    return false;
+  // Default.
+  return group_name == "Enabled";
+}
+#endif
+
 } // namespace content