Bug 1095575 - DoesD3D11DeviceWork() should be overridable by force-enable prefs - r=bas

gfx/thebes/gfxWindowsPlatform.cpp

@@ -1548,6 +1548,13 @@ bool DoesD3D11DeviceWork(ID3D11Device *device)
       return result;
   checked = true;
 
+  if (gfxPrefs::Direct2DForceEnabled() ||
+      gfxPrefs::LayersAccelerationForceEnabled())
+  {
+    result = true;
+    return true;
+  }
+
   if (GetModuleHandleW(L"dlumd32.dll") && GetModuleHandleW(L"igd10umd32.dll")) {
     nsString displayLinkModuleVersionString;
     gfxWindowsPlatform::GetDLLVersion(L"dlumd32.dll", displayLinkModuleVersionString);