Bug 1391996 - Move some checks from nsDisplayText::GetLayerState to constructor to prevent ambiguous status. r=jrmuizel

MozReview-Commit-ID: QPSIqLz56p

--HG--
extra : rebase_source : 1c4db4b0111126b79f4d3e5ab8f693545f1cbd70

layout/generic/nsTextFrame.cpp

@@ -5150,6 +5150,10 @@ nsDisplayText::nsDisplayText(nsDisplayListBuilder* aBuilder, nsTextFrame* aFrame
 
     // TODO: Paint() checks mDisableSubpixelAA, we should too.
     RenderToContext(captureCtx, mTextDrawer, aBuilder, true);
+
+    if (!mTextDrawer->CanSerializeFonts()) {
+      mTextDrawer = nullptr;
+    }
   }
 }
 
@@ -5159,9 +5163,7 @@ nsDisplayText::GetLayerState(nsDisplayListBuilder* aBuilder,
                              const ContainerLayerParameters& aParameters)
 {
   // Basic things that all advanced backends need
-  if (!mTextDrawer ||
+  if (!mTextDrawer) {
-      !mTextDrawer->CanSerializeFonts() ||
-      XRE_IsParentProcess()) {
     return mozilla::LAYER_NONE;
   }