--- a/gfx/layers/client/ClientContainerLayer.h
+++ b/gfx/layers/client/ClientContainerLayer.h
@@ -61,21 +61,17 @@ public:
     readback.BuildUpdates(this);
 
     for (uint32_t i = 0; i < children.Length(); i++) {
       Layer* child = children.ElementAt(i);
       if (child->GetEffectiveVisibleRegion().IsEmpty()) {
         continue;
       }
 
-      if (child->GetType() != TYPE_THEBES) {
-        ToClientLayer(child)->RenderLayer();
-      } else {
-        static_cast<ClientThebesLayer*>(child)->RenderLayer(&readback);
-      }
+      ToClientLayer(child)->RenderLayerWithReadback(&readback);
 
       if (!ClientManager()->GetRepeatTransaction() &&
           !child->GetInvalidRegion().IsEmpty()) {
         child->Mutated();
       }
     }
   }
 

--- a/gfx/layers/client/ClientLayerManager.h
+++ b/gfx/layers/client/ClientLayerManager.h
@@ -329,16 +329,17 @@ public:
     // free them here (it's hard to get that right on emergency
     // shutdown anyway).
     mShadow = nullptr;
   }
 
   virtual void ClearCachedResources() { }
 
   virtual void RenderLayer() = 0;
+  virtual void RenderLayerWithReadback(ReadbackProcessor *aReadback) { RenderLayer(); }
 
   virtual ClientThebesLayer* AsThebes() { return nullptr; }
 
   static inline ClientLayer *
   ToClientLayer(Layer* aLayer)
   {
     return static_cast<ClientLayer*>(aLayer->ImplData());
   }

--- a/gfx/layers/client/ClientThebesLayer.cpp
+++ b/gfx/layers/client/ClientThebesLayer.cpp
@@ -100,17 +100,17 @@ ClientThebesLayer::PaintThebes()
     ClientManager()->Hold(this);
     contentClientRemote->Updated(state.mRegionToDraw,
                                  mVisibleRegion,
                                  state.mDidSelfCopy);
   }
 }
 
 void
-ClientThebesLayer::RenderLayer(ReadbackProcessor *aReadback)
+ClientThebesLayer::RenderLayerWithReadback(ReadbackProcessor *aReadback)
 {
   if (GetMaskLayer()) {
     ToClientLayer(GetMaskLayer())->RenderLayer();
   }
   
   if (!mContentClient) {
     mContentClient = ContentClient::CreateContentClient(ClientManager()->AsShadowForwarder());
     if (!mContentClient) {

--- a/gfx/layers/client/ClientThebesLayer.h
+++ b/gfx/layers/client/ClientThebesLayer.h
@@ -64,19 +64,19 @@ public:
   {
     NS_ASSERTION(ClientManager()->InConstruction(),
                  "Can only set properties in construction phase");
     mInvalidRegion.Or(mInvalidRegion, aRegion);
     mInvalidRegion.SimplifyOutward(20);
     mValidRegion.Sub(mValidRegion, mInvalidRegion);
   }
 
-  virtual void RenderLayer() { RenderLayer(nullptr); }
+  virtual void RenderLayer() { RenderLayerWithReadback(nullptr); }
 
-  virtual void RenderLayer(ReadbackProcessor *aReadback);
+  virtual void RenderLayerWithReadback(ReadbackProcessor *aReadback) MOZ_OVERRIDE;
 
   virtual void ClearCachedResources()
   {
     if (mContentClient) {
       mContentClient->Clear();
     }
     mValidRegion.SetEmpty();
     DestroyBackBuffer();