diff --git a/widget/src/windows/GfxInfo.cpp b/widget/src/windows/GfxInfo.cpp
index aebb4c21ae3..8fd5e20ba8a 100644
--- a/widget/src/windows/GfxInfo.cpp
+++ b/widget/src/windows/GfxInfo.cpp
@@ -353,9 +353,7 @@ GfxInfo::Init()
         setupGetDeviceRegistryProperty &&
         setupDestroyDeviceInfoList) {
       /* create a device information set composed of the current display device */
-      HDEVINFO devinfo = setupGetClassDevs(NULL,
-                                           PromiseFlatString(mDeviceID).get(),
-                                           NULL,
+      HDEVINFO devinfo = setupGetClassDevs(NULL, mDeviceID.get(), NULL,
                                            DIGCF_PRESENT | DIGCF_PROFILE | DIGCF_ALLCLASSES);
 
       if (devinfo != INVALID_HANDLE_VALUE) {
diff --git a/widget/src/xpwidgets/GfxDriverInfo.h b/widget/src/xpwidgets/GfxDriverInfo.h
index e0c8c1844fa..d70c4f52319 100644
--- a/widget/src/xpwidgets/GfxDriverInfo.h
+++ b/widget/src/xpwidgets/GfxDriverInfo.h
@@ -122,7 +122,7 @@ ParseDriverVersion(nsAString& aVersion, PRUint64 *aNumericVersion)
 {
   int a, b, c, d;
   /* honestly, why do I even bother */
-  if (sscanf(nsPromiseFlatCString(NS_LossyConvertUTF16toASCII(aVersion)).get(),
+  if (sscanf(NS_LossyConvertUTF16toASCII(aVersion).get(),
              "%d.%d.%d.%d", &a, &b, &c, &d) != 4)
     return false;
   if (a < 0 || a > 0xffff) return false;
diff --git a/widget/src/xpwidgets/GfxInfoBase.cpp b/widget/src/xpwidgets/GfxInfoBase.cpp
index 0a81d8dad6d..bd3b9f02962 100644
--- a/widget/src/xpwidgets/GfxInfoBase.cpp
+++ b/widget/src/xpwidgets/GfxInfoBase.cpp
@@ -665,7 +665,7 @@ NS_IMETHODIMP GfxInfoBase::GetFailures(PRUint32 *failureCount NS_OUTPARAM, char
 
     /* copy over the failure messages into the array we just allocated */
     for (PRUint32 i = 0; i < *failureCount; i++) {
-      nsPromiseFlatCString flattenedFailureMessage(mFailures[i]);
+      nsCString& flattenedFailureMessage(mFailures[i]);
       (*failures)[i] = (char*)nsMemory::Clone(flattenedFailureMessage.get(), flattenedFailureMessage.Length() + 1);
 
       if (!(*failures)[i]) {