Bug 1511438 Part 1: Replace ProcessTypeRequiresWinEventHook with XRE_Win32kCallsAllowed. r=froydnj

ProcessTypeRequiresWinEventHook was added when attempting to turn on win32k
lockdown for GMP processes. Having a less specific, but globally accessible,
function will make it more useful while applying win32k lockdown to other
process types.

ipc/glue/WindowsMessageLoop.cpp

@@ -634,15 +634,6 @@ namespace mozilla {
 namespace ipc {
 namespace windows {
 
-static bool ProcessTypeRequiresWinEventHook() {
-  switch (XRE_GetProcessType()) {
-    case GeckoProcessType_GMPlugin:
-      return false;
-    default:
-      return true;
-  }
-}
-
 void InitUIThread() {
   // If we aren't setup before a call to NotifyWorkerThread, we'll hang
   // on startup.
@@ -654,7 +645,7 @@ void InitUIThread() {
   MOZ_ASSERT(gUIThreadId == GetCurrentThreadId(),
              "Called InitUIThread multiple times on different threads!");
 
-  if (!gWinEventHook && ProcessTypeRequiresWinEventHook()) {
+  if (!gWinEventHook && XRE_Win32kCallsAllowed()) {
     gWinEventHook = SetWinEventHook(EVENT_OBJECT_CREATE, EVENT_OBJECT_DESTROY,
                                     NULL, &WinEventHook, GetCurrentProcessId(),
                                     gUIThreadId, WINEVENT_OUTOFCONTEXT);

toolkit/xre/nsAppRunner.cpp

@@ -4734,6 +4734,18 @@ bool XRE_UseNativeEventProcessing() {
   return true;
 }
 
+#if defined(XP_WIN)
+bool XRE_Win32kCallsAllowed() {
+  switch (XRE_GetProcessType()) {
+    case GeckoProcessType_GMPlugin:
+    case GeckoProcessType_RDD:
+      return false;
+    default:
+      return true;
+  }
+}
+#endif
+
 // If you add anything to this enum, please update about:support to reflect it
 enum {
   kE10sEnabledByUser = 0,

xpcom/build/nsXULAppAPI.h

@@ -451,6 +451,14 @@ XRE_API(bool, XRE_IsSocketProcess, ())
  */
 XRE_API(bool, XRE_UseNativeEventProcessing, ())
 
+#if defined(XP_WIN)
+/**
+ * @returns true if win32k calls are allowed in this process type, false if
+ *          win32k is (or should be) disabled.
+ */
+XRE_API(bool, XRE_Win32kCallsAllowed, ())
+#endif
+
 typedef void (*MainFunction)(void* aData);
 
 XRE_API(nsresult, XRE_InitParentProcess,