Remove RenderPart.

sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp

Index: sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp
diff --git a/sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp b/sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp
index 2399b525293721a6211b174232750337903ea457..de9a81fcdc853f2c9aea1502af949765e4b34e92 100644
--- a/sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp
+++ b/sky/engine/core/rendering/compositing/CompositingLayerAssigner.cpp
@@ -130,11 +130,6 @@ CompositingReasons CompositingLayerAssigner::getReasonsPreventingSquashing(const
     if (layer->renderer()->isVideo())
         return CompositingReasonSquashingVideoIsDisallowed;
 
-    // Don't squash iframes, frames or plugins.
-    // FIXME: this is only necessary because there is frame code that assumes that composited frames are not squashed.
-    if (layer->renderer()->isRenderPart())
-        return CompositingReasonSquashingRenderPartIsDisallowed;
-
     if (squashingWouldExceedSparsityTolerance(layer, squashingState))
         return CompositingReasonSquashingSparsityExceeded;