Clean up paint invalidation container logic for RenderText.

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 7c7a927b2e69365484122abad4d332f73df97f1c..5519d5f9be98e814ad1a4e8efb77bc87de1cf4b7 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -562,9 +562,8 @@ RenderLayer* RenderObject::enclosingLayer() const
         if (current->hasLayer())
             return toRenderLayerModelObject(current)->layer();
     }
-    // FIXME: We should remove the one caller that triggers this case and make
-    // this function return a reference.
-    ASSERT(!m_parent && !isRenderView());
+    // FIXME: we should get rid of detached render subtrees, at which point this code should
+    // not be reached. crbug.com/411429
     return 0;
 }