Bug 970483 - Fix the logic to determine the pre-RTM Windows 7. r=bbondy

gfx/thebes/gfxWindowsPlatform.cpp

@@ -628,7 +628,7 @@ gfxWindowsPlatform::CreatePlatformFontList()
 #ifdef CAIRO_HAS_DWRITE_FONT
     // bug 630201 - older pre-RTM versions of Direct2D/DirectWrite cause odd
     // crashers so blacklist them altogether
-    if (IsWin7RTMOrLater() && GetDWriteFactory()) {
+    if (IsNotWin7PreRTM() && GetDWriteFactory()) {
         pfl = new gfxDWriteFontList();
         if (NS_SUCCEEDED(pfl->InitFontList())) {
             return pfl;

xpcom/base/WindowsVersion.h

@@ -114,10 +114,10 @@ namespace mozilla
   { return IsWindowsVersionOrLater(0x06020000ul); }
 
   MOZ_ALWAYS_INLINE bool
-  IsWin7RTMOrLater()
+  IsNotWin7PreRTM()
   {
-    return IsWin7SP1OrLater() ||
-           (IsWin7OrLater() && IsWindowsBuildOrLater(7600));
+    return IsWin7SP1OrLater() || !IsWin7OrLater() ||
+           IsWindowsBuildOrLater(7600);
   }
 }