Use correct cascading order for Shadow DOM v1

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 960c8a3a28a5fbb1221c8bacf4be72b22c6b0fcc..08c99827126ee6d97a6d1f7fc83b58466c01ff55 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -1906,6 +1906,8 @@ PassRefPtrWillBeRawPtr<ShadowRoot> Element::createShadowRoot(const ScriptState*
             return nullptr;
         }
     }
+    document().styleEngine().setShadowCascadeOrder(ShadowCascadeOrder::ShadowCascadeV0);
+
     return createShadowRootInternal(ShadowRootType::V0, exceptionState);
 }
 
@@ -1944,6 +1946,8 @@ PassRefPtrWillBeRawPtr<ShadowRoot> Element::attachShadow(const ScriptState* scri
         return nullptr;
     }
 
+    document().styleEngine().setShadowCascadeOrder(ShadowCascadeOrder::ShadowCascadeV1);
+
     ShadowRootType type = ShadowRootType::V0;
     if (shadowRootInitDict.hasMode())
         type = shadowRootInitDict.mode() == "open" ? ShadowRootType::Open : ShadowRootType::Closed;