Have Element::ensureUserAgentShadowRoot() return a reference

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index db7ace97e2c10869333f046d87afa13bb59f4c0a..183c8edc156f8d2ebbb0f6ee66d86c5a8ce093e4 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1684,7 +1684,7 @@ PassRefPtr<ShadowRoot> Element::createShadowRoot(ExceptionState& es)
         ensureUserAgentShadowRoot();
 
     if (RuntimeEnabledFeatures::authorShadowDOMForAnyElementEnabled())
-        return ensureShadow().addShadowRoot(*this, ShadowRoot::AuthorShadowRoot);
+        return PassRefPtr<ShadowRoot>(ensureShadow().addShadowRoot(*this, ShadowRoot::AuthorShadowRoot));
 
     // Since some elements recreates shadow root dynamically, multiple shadow
     // subtrees won't work well in that element. Until they are fixed, we disable
@@ -1693,7 +1693,7 @@ PassRefPtr<ShadowRoot> Element::createShadowRoot(ExceptionState& es)
         es.throwUninformativeAndGenericDOMException(HierarchyRequestError);
         return 0;
     }
-    return ensureShadow().addShadowRoot(*this, ShadowRoot::AuthorShadowRoot);
+    return PassRefPtr<ShadowRoot>(ensureShadow().addShadowRoot(*this, ShadowRoot::AuthorShadowRoot));
 }
 
 ShadowRoot* Element::shadowRoot() const
@@ -1723,11 +1723,11 @@ ShadowRoot* Element::userAgentShadowRoot() const
     return 0;
 }
 
-ShadowRoot* Element::ensureUserAgentShadowRoot()
+ShadowRoot& Element::ensureUserAgentShadowRoot()
 {
     if (ShadowRoot* shadowRoot = userAgentShadowRoot())
-        return shadowRoot;
-    ShadowRoot* shadowRoot = ensureShadow().addShadowRoot(*this, ShadowRoot::UserAgentShadowRoot);
+        return *shadowRoot;
+    ShadowRoot& shadowRoot = ensureShadow().addShadowRoot(*this, ShadowRoot::UserAgentShadowRoot);
     didAddUserAgentShadowRoot(shadowRoot);
     return shadowRoot;
 }