Bug 1561235. Check the type of the PathBuilder instead of the DrawTarget. r=mstange

The draw target might give us a different type.

Differential Revision: https://phabricator.services.mozilla.com/D36830

--HG--
extra : moz-landing-system : lando

gfx/2d/ScaledFontDWrite.cpp

@@ -149,13 +149,14 @@ ScaledFontDWrite::ScaledFontDWrite(IDWriteFontFace* aFontFace,
 
 already_AddRefed<Path> ScaledFontDWrite::GetPathForGlyphs(
     const GlyphBuffer& aBuffer, const DrawTarget* aTarget) {
-  if (aTarget->GetBackendType() != BackendType::DIRECT2D &&
-      aTarget->GetBackendType() != BackendType::DIRECT2D1_1) {
-    return ScaledFontBase::GetPathForGlyphs(aBuffer, aTarget);
-  }
 
   RefPtr<PathBuilder> pathBuilder = aTarget->CreatePathBuilder();
 
+  if (pathBuilder->GetBackendType() != BackendType::DIRECT2D &&
+      pathBuilder->GetBackendType() != BackendType::DIRECT2D1_1) {
+    return ScaledFontBase::GetPathForGlyphs(aBuffer, aTarget);
+  }
+
   PathBuilderD2D* pathBuilderD2D =
       static_cast<PathBuilderD2D*>(pathBuilder.get());