Make ElementRareData::ensureShadow() 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 eed37fbb737fe47d67f6dd8263d62a20e9dfca75..583ab8483a72cbdc826ed93f4664abe671ca3749 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1677,7 +1677,7 @@ ElementShadow* Element::shadow() const
     return hasRareData() ? elementRareData()->shadow() : 0;
 }
 
-ElementShadow* Element::ensureShadow()
+ElementShadow& Element::ensureShadow()
 {
     return ensureElementRareData()->ensureShadow();
 }
@@ -1695,7 +1695,7 @@ PassRefPtr<ShadowRoot> Element::createShadowRoot(ExceptionState& es)
         ensureUserAgentShadowRoot();
 
     if (RuntimeEnabledFeatures::authorShadowDOMForAnyElementEnabled())
-        return ensureShadow()->addShadowRoot(this, ShadowRoot::AuthorShadowRoot);
+        return 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
@@ -1704,7 +1704,7 @@ PassRefPtr<ShadowRoot> Element::createShadowRoot(ExceptionState& es)
         es.throwUninformativeAndGenericDOMException(HierarchyRequestError);
         return 0;
     }
-    return ensureShadow()->addShadowRoot(this, ShadowRoot::AuthorShadowRoot);
+    return ensureShadow().addShadowRoot(this, ShadowRoot::AuthorShadowRoot);
 }
 
 ShadowRoot* Element::shadowRoot() const
@@ -1738,7 +1738,7 @@ ShadowRoot* Element::ensureUserAgentShadowRoot()
 {
     if (ShadowRoot* shadowRoot = userAgentShadowRoot())
         return shadowRoot;
-    ShadowRoot* shadowRoot = ensureShadow()->addShadowRoot(this, ShadowRoot::UserAgentShadowRoot);
+    ShadowRoot* shadowRoot = ensureShadow().addShadowRoot(this, ShadowRoot::UserAgentShadowRoot);
     didAddUserAgentShadowRoot(shadowRoot);
     return shadowRoot;
 }