Have Node::document() return a reference instead of a pointer

Source/core/html/HTMLProgressElement.cpp

Index: Source/core/html/HTMLProgressElement.cpp
diff --git a/Source/core/html/HTMLProgressElement.cpp b/Source/core/html/HTMLProgressElement.cpp
index 11f3b36ff2f37b9e4902b1b6053e1e0e8bea98bb..97d12d6ae0439f12ce36873bb288fe9f24475ac5 100644
--- a/Source/core/html/HTMLProgressElement.cpp
+++ b/Source/core/html/HTMLProgressElement.cpp
@@ -150,13 +150,13 @@ void HTMLProgressElement::didAddUserAgentShadowRoot(ShadowRoot* root)
 {
     ASSERT(!m_value);
 
-    RefPtr<ProgressInnerElement> inner = ProgressInnerElement::create(document());
+    RefPtr<ProgressInnerElement> inner = ProgressInnerElement::create(&document());
     inner->setPart(AtomicString("-webkit-progress-inner-element", AtomicString::ConstructFromLiteral));
     root->appendChild(inner);
 
-    RefPtr<ProgressBarElement> bar = ProgressBarElement::create(document());
+    RefPtr<ProgressBarElement> bar = ProgressBarElement::create(&document());
     bar->setPart(AtomicString("-webkit-progress-bar", AtomicString::ConstructFromLiteral));
-    RefPtr<ProgressValueElement> value = ProgressValueElement::create(document());
+    RefPtr<ProgressValueElement> value = ProgressValueElement::create(&document());
     m_value = value.get();
     m_value->setPart(AtomicString("-webkit-progress-value", AtomicString::ConstructFromLiteral));
     m_value->setWidthPercentage(HTMLProgressElement::IndeterminatePosition * 100);