Fix asserts to account for the fact that SVG may have contains: paint.

third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp
index 8785ee1b8ec6fca0498569f0296323e0184eb8e6..a7f1b1bf3b8141b4db979bfd6956262a82008750 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositingInputsUpdater.cpp
@@ -39,7 +39,7 @@ static const PaintLayer* findParentLayerOnClippingContainerChain(const PaintLaye
                 // CSS clip applies to fixed position elements even for ancestors that are not what the
                 // fixed element is positioned with respect to.
                 if (current->hasClip()) {
-                    ASSERT(current->hasLayer());
+                    DCHECK(current->hasLayer());
                     return static_cast<const LayoutBoxModelObject*>(current)->layer();
                 }
             }
@@ -49,8 +49,9 @@ static const PaintLayer* findParentLayerOnClippingContainerChain(const PaintLaye
 
         if (current->hasLayer())
             return static_cast<const LayoutBoxModelObject*>(current)->layer();
-        // Having clip or overflow clip forces the LayoutObject to become a layer.
-        ASSERT(!current->hasClipRelatedProperty());
+        // Having clip or overflow clip forces the LayoutObject to become a layer, except for contains: paint, which may apply to SVG.

[fs, 2016/06/13 20:03:56]

"...which may apply to SVG elements without forcing a layer. (SVG elements in
general cannot have PaintLayers.)"

Maybe?

[chrishtr, 2016/06/13 20:08:06]

Done.

+        // SVG cannot have PaintLayers.

[pdr., 2016/06/13 20:05:51]

It may be useful to clarify that this PaintLayer restriction doesn't apply to
the root, which can have a paint layer.

[chrishtr, 2016/06/13 20:08:06]

Done.

+        DCHECK(!current->hasClipRelatedProperty() || current->styleRef().containsPaint());
     }
     ASSERT_NOT_REACHED();
     return nullptr;