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

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 99218f852b05ae1b1877c0567bdb216889ca18a3..689e36c6d1ee9f8e74c2ddc80717147a26099333 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -136,7 +136,7 @@ void RenderObject::operator delete(void* ptr)
 
 RenderObject* RenderObject::createObject(Element* element, RenderStyle* style)
 {
-    Document* doc = element->document();
+    Document& doc = element->document();
 
     // Minimal support for content properties replacing an entire element.
     // Works only if we have exactly one piece of content and it's a URL.
@@ -166,13 +166,13 @@ RenderObject* RenderObject::createObject(Element* element, RenderStyle* style)
     // treat <rt> as ruby text ONLY if it still has its default treatment of block
     if (element->hasTagName(rtTag) && style->display() == BLOCK)
         return new RenderRubyText(element);
-    if (RuntimeEnabledFeatures::cssRegionsEnabled() && style->isDisplayRegionType() && !style->regionThread().isEmpty() && doc->renderView())
+    if (RuntimeEnabledFeatures::cssRegionsEnabled() && style->isDisplayRegionType() && !style->regionThread().isEmpty() && doc.renderView())
         return new RenderRegion(element, 0);
 
     if (style->display() == RUN_IN)
-        UseCounter::count(doc, UseCounter::CSSDisplayRunIn);
+        UseCounter::count(&doc, UseCounter::CSSDisplayRunIn);
     else if (style->display() == COMPACT)
-        UseCounter::count(doc, UseCounter::CSSDisplayCompact);
+        UseCounter::count(&doc, UseCounter::CSSDisplayCompact);
 
     switch (style->display()) {
     case NONE:
@@ -183,7 +183,7 @@ RenderObject* RenderObject::createObject(Element* element, RenderStyle* style)
     case INLINE_BLOCK:
     case RUN_IN:
     case COMPACT:
-        if ((!style->hasAutoColumnCount() || !style->hasAutoColumnWidth()) && doc->regionBasedColumnsEnabled())
+        if ((!style->hasAutoColumnCount() || !style->hasAutoColumnWidth()) && doc.regionBasedColumnsEnabled())
             return new RenderMultiColumnBlock(element);
         return new RenderBlock(element);
     case LIST_ITEM:
@@ -1139,12 +1139,12 @@ void RenderObject::addPDFURLRect(GraphicsContext* context, const LayoutRect& rec
     const AtomicString& href = toElement(n)->getAttribute(hrefAttr);
     if (href.isNull())
         return;
-    KURL url = n->document()->completeURL(href);
+    KURL url = n->document().completeURL(href);
     if (!url.isValid())
         return;
-    if (context->supportsURLFragments() && url.hasFragmentIdentifier() && equalIgnoringFragmentIdentifier(url, n->document()->baseURL())) {
+    if (context->supportsURLFragments() && url.hasFragmentIdentifier() && equalIgnoringFragmentIdentifier(url, n->document().baseURL())) {
         String name = url.fragmentIdentifier();
-        if (document()->findAnchor(name))
+        if (document().findAnchor(name))
             context->setURLFragmentForRect(name, pixelSnappedIntRect(rect));
         return;
     }
@@ -1320,7 +1320,7 @@ RenderLayerModelObject* RenderObject::containerForRepaint() const
         }
     }
 
-    if (document()->view()->hasSoftwareFilters()) {
+    if (document().view()->hasSoftwareFilters()) {
         if (RenderLayer* parentLayer = enclosingLayer()) {
             RenderLayer* enclosingFilterLayer = parentLayer->enclosingFilterLayer();
             if (enclosingFilterLayer)
@@ -1335,7 +1335,7 @@ RenderLayerModelObject* RenderObject::containerForRepaint() const
     if (parentRenderFlowThread) {
         // The ancestor document will do the reparenting when the repaint propagates further up.
         // We're just a seamless child document, and we don't need to do the hacking.
-        if (parentRenderFlowThread && parentRenderFlowThread->document() != document())
+        if (&parentRenderFlowThread && &parentRenderFlowThread->document() != &document())
             return repaintContainer;
         // If we have already found a repaint container then we will repaint into that container only if it is part of the same
         // flow thread. Otherwise we will need to catch the repaint call and send it to the flow thread.
@@ -1542,7 +1542,7 @@ bool RenderObject::repaintAfterLayoutIfNeeded(const RenderLayerModelObject* repa
 
 bool RenderObject::checkForRepaintDuringLayout() const
 {
-    return !document()->view()->needsFullRepaint() && !hasLayer() && everHadLayout();
+    return !document().view()->needsFullRepaint() && !hasLayer() && everHadLayout();
 }
 
 LayoutRect RenderObject::rectWithOutlineForRepaint(const RenderLayerModelObject* repaintContainer, LayoutUnit outlineWidth) const
@@ -1914,8 +1914,8 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle* newS
                 || m_style->zIndex() != newStyle->zIndex()
                 || m_style->hasAutoZIndex() != newStyle->hasAutoZIndex();
             if (visibilityChanged) {
-                document()->setAnnotatedRegionsDirty(true);
-                if (AXObjectCache* cache = document()->existingAXObjectCache())
+                document().setAnnotatedRegionsDirty(true);
+                if (AXObjectCache* cache = document().existingAXObjectCache())
                     cache->childrenChanged(parent());
             }
 
@@ -1974,7 +1974,7 @@ void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle* newS
         bool newStyleSlowScroll = newStyle && !shouldBlitOnFixedBackgroundImage && newStyle->hasFixedBackgroundImage();
         bool oldStyleSlowScroll = m_style && !shouldBlitOnFixedBackgroundImage && m_style->hasFixedBackgroundImage();
 
-        bool drawsRootBackground = isRoot() || (isBody() && !rendererHasBackground(document()->documentElement()->renderer()));
+        bool drawsRootBackground = isRoot() || (isBody() && !rendererHasBackground(document().documentElement()->renderer()));
         if (drawsRootBackground && !shouldBlitOnFixedBackgroundImage) {
             if (view()->compositor()->supportsFixedRootBackgroundCompositing()) {
                 if (newStyleSlowScroll && newStyle->hasEntirelyFixedBackground())
@@ -2373,7 +2373,7 @@ RenderObject* RenderObject::rendererForRootBackground()
         // to crawl around a render tree with potential :before/:after content and
         // anonymous blocks created by inline <body> tags etc. We can locate the <body>
         // render object very easily via the DOM.
-        HTMLElement* body = document()->body();
+        HTMLElement* body = document().body();
         RenderObject* bodyObject = (body && body->hasLocalName(bodyTag)) ? body->renderer() : 0;
         if (bodyObject)
             return bodyObject;
@@ -2386,13 +2386,13 @@ RespectImageOrientationEnum RenderObject::shouldRespectImageOrientation() const
 {
     // Respect the image's orientation if it's being used as a full-page image or it's
     // an <img> and the setting to respect it everywhere is set.
-    return document()->isImageDocument() ||
-        (document()->settings() && document()->settings()->shouldRespectImageOrientation() && node() && node()->hasTagName(HTMLNames::imgTag)) ? RespectImageOrientation : DoNotRespectImageOrientation;
+    return document().isImageDocument()
+        || (document().settings() && document().settings()->shouldRespectImageOrientation() && node() && node()->hasTagName(HTMLNames::imgTag)) ? RespectImageOrientation : DoNotRespectImageOrientation;
 }
 
 bool RenderObject::hasOutlineAnnotation() const
 {
-    return node() && node()->isLink() && document()->printing();
+    return node() && node()->isLink() && document().printing();
 }
 
 bool RenderObject::hasEntirelyFixedBackground() const
@@ -2504,14 +2504,14 @@ void RenderObject::willBeDestroyed()
 
     // For accessibility management, notify the parent of the imminent change to its child set.
     // We do it now, before remove(), while the parent pointer is still available.
-    if (AXObjectCache* cache = document()->existingAXObjectCache())
+    if (AXObjectCache* cache = document().existingAXObjectCache())
         cache->childrenChanged(this->parent());
 
     remove();
 
     // The remove() call above may invoke axObjectCache()->childrenChanged() on the parent, which may require the AX render
     // object for this renderer. So we remove the AX render object now, after the renderer is removed.
-    if (AXObjectCache* cache = document()->existingAXObjectCache())
+    if (AXObjectCache* cache = document().existingAXObjectCache())
         cache->remove(this);
 
 #ifndef NDEBUG
@@ -2843,7 +2843,7 @@ static PassRefPtr<RenderStyle> firstLineStyleForCachedUncachedType(StyleCacheSta
 
 PassRefPtr<RenderStyle> RenderObject::uncachedFirstLineStyle(RenderStyle* style) const
 {
-    if (!document()->styleSheetCollections()->usesFirstLineRules())
+    if (!document().styleSheetCollections()->usesFirstLineRules())
         return 0;
 
     ASSERT(!isText());
@@ -2853,7 +2853,7 @@ PassRefPtr<RenderStyle> RenderObject::uncachedFirstLineStyle(RenderStyle* style)
 
 RenderStyle* RenderObject::cachedFirstLineStyle() const
 {
-    ASSERT(document()->styleSheetCollections()->usesFirstLineRules());
+    ASSERT(document().styleSheetCollections()->usesFirstLineRules());
 
     if (RefPtr<RenderStyle> style = firstLineStyleForCachedUncachedType(Cached, isText() ? parent() : this, m_style.get()))
         return style.get();
@@ -2895,12 +2895,12 @@ PassRefPtr<RenderStyle> RenderObject::getUncachedPseudoStyle(const PseudoStyleRe
     Element* element = toElement(n);
 
     if (pseudoStyleRequest.pseudoId == FIRST_LINE_INHERITED) {
-        RefPtr<RenderStyle> result = document()->styleResolver()->styleForElement(element, parentStyle, DisallowStyleSharing);
+        RefPtr<RenderStyle> result = document().styleResolver()->styleForElement(element, parentStyle, DisallowStyleSharing);
         result->setStyleType(FIRST_LINE_INHERITED);
         return result.release();
     }
 
-    return document()->styleResolver()->pseudoStyleForElement(element, pseudoStyleRequest, parentStyle);
+    return document().styleResolver()->pseudoStyleForElement(element, pseudoStyleRequest, parentStyle);
 }
 
 bool RenderObject::hasBlendMode() const
@@ -3008,12 +3008,12 @@ bool RenderObject::willRenderImage(ImageResource*)
         return false;
 
     // We will not render a new image when Active DOM is suspended
-    if (document()->activeDOMObjectsAreSuspended())
+    if (document().activeDOMObjectsAreSuspended())
         return false;
 
     // If we're not in a window (i.e., we're dormant from being in a background tab)
     // then we don't want to render either.
-    return !document()->view()->isOffscreen();
+    return !document().view()->isOffscreen();
 }
 
 int RenderObject::maximalOutlineSize(PaintPhase p) const
@@ -3127,7 +3127,7 @@ Element* RenderObject::offsetParent() const
 
         // CSS regions specification says that region flows should return the body element as their offsetParent.
         if (ancestor->isRenderNamedFlowThread())
-            return document()->body();
+            return document().body();
 
         node = ancestor->node();