Remove useless null checks from Node::document() call sites

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 177 matching lines @@
 }
 
 PassRefPtr<Element> Element::create(const QualifiedName& tagName, Document* document)
 {
     return adoptRef(new Element(tagName, document, CreateElement));
 }
 
 Element::~Element()
 {
 #ifndef NDEBUG
-    if (document() && document()->renderer()) {
+    if (document()->renderer()) {
         // When the document is not destroyed, an element that was part of a named flow
         // content nodes should have been removed from the content nodes collection
         // and the inNamedFlow flag reset.
         ASSERT(!inNamedFlow());
     }
 #endif
 
     if (PropertySetCSSStyleDeclaration* cssomWrapper = inlineStyleCSSOMWrapper())
         cssomWrapper->clearParentElement();
 
@@ skipping 910 matching lines @@
 
 void Element::parserSetAttributes(const Vector<Attribute>& attributeVector)
 {
     ASSERT(!inDocument());
     ASSERT(!parentNode());
     ASSERT(!m_elementData);
 
     if (attributeVector.isEmpty())
         return;
 
-    if (document() && document()->sharedObjectPool())
+    if (document()->sharedObjectPool())
         m_elementData = document()->sharedObjectPool()->cachedShareableElementDataWithAttributes(attributeVector);
     else
         m_elementData = ShareableElementData::createWithAttributes(attributeVector);
 
     // Use attributeVector instead of m_elementData because attributeChanged might modify m_elementData.
     for (unsigned i = 0; i < attributeVector.size(); ++i)
         attributeChangedFromParserOrByCloning(attributeVector[i].name(), attributeVector[i].value(), ModifiedDirectly);
 }
 
 bool Element::hasAttributes() const
@@ skipping 2090 matching lines @@
     } else {
         ASSERT(inlineStyle->isMutable());
         static_pointer_cast<MutableStylePropertySet>(inlineStyle)->parseDeclaration(newStyleString, document()->elementSheet()->contents());
     }
 }
 
 void Element::styleAttributeChanged(const AtomicString& newStyleString, AttributeModificationReason modificationReason)
 {
     ASSERT(isStyledElement());
     WTF::OrdinalNumber startLineNumber = WTF::OrdinalNumber::beforeFirst();
-    if (document() && document()->scriptableDocumentParser() && !document()->isInDocumentWrite())
+    if (document()->scriptableDocumentParser() && !document()->isInDocumentWrite())
         startLineNumber = document()->scriptableDocumentParser()->lineNumber();
 
     if (newStyleString.isNull()) {
         if (PropertySetCSSStyleDeclaration* cssomWrapper = inlineStyleCSSOMWrapper())
             cssomWrapper->clearParentElement();
         ensureUniqueElementData()->m_inlineStyle.clear();
     } else if (modificationReason == ModifiedByCloning || document()->contentSecurityPolicy()->allowInlineStyle(document()->url(), startLineNumber)) {
         setInlineStyleFromString(newStyleString);
     }
 
@@ skipping 383 matching lines @@
     return 0;
 }
 
 Attribute* UniqueElementData::attributeItem(unsigned index)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(index < length());
     return &m_attributeVector.at(index);
 }
 
 } // namespace WebCore