Added directwrite warmup for PPAPI processes.

content/ppapi_plugin/ppapi_thread.cc

Index: content/ppapi_plugin/ppapi_thread.cc
diff --git a/content/ppapi_plugin/ppapi_thread.cc b/content/ppapi_plugin/ppapi_thread.cc
index 6b2dc122a0ede2a332736be5f645593cfd8f701b..907b12b0f5cdb6011e51969a429a0275aecbb18c 100644
--- a/content/ppapi_plugin/ppapi_thread.cc
+++ b/content/ppapi_plugin/ppapi_thread.cc
@@ -10,6 +10,7 @@
 #include "base/cpu.h"
 #include "base/debug/crash_logging.h"
 #include "base/files/file_util.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/discardable_memory_allocator.h"
 #include "base/metrics/histogram.h"
@@ -97,8 +98,49 @@ static void WarmupWindowsLocales(const ppapi::PpapiPermissions& permissions) {
 
 #endif
 
+typedef decltype(GetProcessMitigationPolicy)* GetProcessMitigationPolicyType;
+
+// Get win32k lockdown policy using a lazy instance so it's only initialized

[palmer, 2015/09/15 21:43:43]

This is copied and pasted from another CL, right? Rather than duplicating it,
put it in a shared location.

[forshaw, 2015/09/15 21:59:32]

I'd love to. Initially I had it in base but wfh@ recommended that would be a
hassle getting it into that from a maintainers perspective. So instead I moved
it to sandbox. But it turns out the skia code can't access sandbox code and I
felt it was probably unwise to change dependencies. So currently at a loss as
where best to put it. I could probably access the one in skia/ext from content,
but that seems a bit sketchy. If you've got a better idea for a place to dump it
I'm all for it.

+// once and is thread-safe.
+class LazyIsWin32kLockdownEnabled {
+ public:
+  LazyIsWin32kLockdownEnabled() : value_(IsWin32kLockdownEnabled()) {}
+
+  ~LazyIsWin32kLockdownEnabled() {}
+
+  bool value() { return value_; }
+
+ private:
+  static bool IsWin32kLockdownEnabled() {
+    GetProcessMitigationPolicyType get_process_mitigation_policy_func =
+        reinterpret_cast<GetProcessMitigationPolicyType>(GetProcAddress(
+            GetModuleHandle(L"kernel32.dll"), "GetProcessMitigationPolicy"));
+
+    if (!get_process_mitigation_policy_func)
+      return false;
+
+    PROCESS_MITIGATION_SYSTEM_CALL_DISABLE_POLICY policy = {0};
+    if (get_process_mitigation_policy_func(GetCurrentProcess(),
+                                           ProcessSystemCallDisablePolicy,
+                                           &policy, sizeof(policy)))
+      return policy.DisallowWin32kSystemCalls != 0;
+
+    return false;
+  }
+
+  const bool value_;
+
+  DISALLOW_COPY_AND_ASSIGN(LazyIsWin32kLockdownEnabled);
+};
+
 namespace content {
 
+bool IsWin32kLockdownEnabled() {
+  static base::LazyInstance<LazyIsWin32kLockdownEnabled> win32k_lockdown =
+      LAZY_INSTANCE_INITIALIZER;
+  return win32k_lockdown.Get().value();
+}
+
 typedef int32_t (*InitializeBrokerFunc)
     (PP_ConnectInstance_Func* connect_instance_func);