Have Frame::tree() return a reference

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 38504b3de8f04428b99f5883625c01a2e05d28a0..5470034f15535910b3b3c541f60dc2329a7fe861 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -318,7 +318,7 @@ static bool canAccessAncestor(const SecurityOrigin* activeSecurityOrigin, Frame*
         return false;
 
     const bool isLocalActiveOrigin = activeSecurityOrigin->isLocal();
-    for (Frame* ancestorFrame = targetFrame; ancestorFrame; ancestorFrame = ancestorFrame->tree()->parent()) {
+    for (Frame* ancestorFrame = targetFrame; ancestorFrame; ancestorFrame = ancestorFrame->tree().parent()) {
         Document* ancestorDocument = ancestorFrame->document();
         // FIXME: Should be an ASSERT? Frames should alway have documents.
         if (!ancestorDocument)
@@ -952,7 +952,7 @@ PassRefPtr<Node> Document::adoptNode(PassRefPtr<Node> source, ExceptionState& es
 
         if (source->isFrameOwnerElement()) {
             HTMLFrameOwnerElement* frameOwnerElement = toHTMLFrameOwnerElement(source.get());
-            if (frame() && frame()->tree()->isDescendantOf(frameOwnerElement->contentFrame())) {
+            if (frame() && frame()->tree().isDescendantOf(frameOwnerElement->contentFrame())) {
                 es.throwUninformativeAndGenericDOMException(HierarchyRequestError);
                 return 0;
             }
@@ -2728,15 +2728,15 @@ bool Document::canNavigate(Frame* targetFrame)
         return true;
 
     // Frame-busting is generally allowed, but blocked for sandboxed frames lacking the 'allow-top-navigation' flag.
-    if (!isSandboxed(SandboxTopNavigation) && targetFrame == m_frame->tree()->top())
+    if (!isSandboxed(SandboxTopNavigation) && targetFrame == m_frame->tree().top())
         return true;
 
     if (isSandboxed(SandboxNavigation)) {
-        if (targetFrame->tree()->isDescendantOf(m_frame))
+        if (targetFrame->tree().isDescendantOf(m_frame))
             return true;
 
         const char* reason = "The frame attempting navigation is sandboxed, and is therefore disallowed from navigating its ancestors.";
-        if (isSandboxed(SandboxTopNavigation) && targetFrame == m_frame->tree()->top())
+        if (isSandboxed(SandboxTopNavigation) && targetFrame == m_frame->tree().top())
             reason = "The frame attempting navigation of the top-level window is sandboxed, but the 'allow-top-navigation' flag is not set.";
 
         printNavigationErrorMessage(targetFrame, url(), reason);
@@ -2764,7 +2764,7 @@ bool Document::canNavigate(Frame* targetFrame)
     // some way related to the frame being navigate (e.g., by the "opener"
     // and/or "parent" relation). Requiring some sort of relation prevents a
     // document from navigating arbitrary, unrelated top-level frames.
-    if (!targetFrame->tree()->parent()) {
+    if (!targetFrame->tree().parent()) {
         if (targetFrame == m_frame->loader()->opener())
             return true;
 
@@ -2779,13 +2779,13 @@ bool Document::canNavigate(Frame* targetFrame)
 Frame* Document::findUnsafeParentScrollPropagationBoundary()
 {
     Frame* currentFrame = m_frame;
-    Frame* ancestorFrame = currentFrame->tree()->parent();
+    Frame* ancestorFrame = currentFrame->tree().parent();
 
     while (ancestorFrame) {
         if (!ancestorFrame->document()->securityOrigin()->canAccess(securityOrigin()))
             return currentFrame;
         currentFrame = ancestorFrame;
-        ancestorFrame = ancestorFrame->tree()->parent();
+        ancestorFrame = ancestorFrame->tree().parent();
     }
     return 0;
 }
@@ -3211,7 +3211,7 @@ void Document::notifySeamlessChildDocumentsOfStylesheetUpdate() const
         return;
 
     // Seamless child frames are expected to notify their seamless children recursively, so we only do direct children.
-    for (Frame* child = frame()->tree()->firstChild(); child; child = child->tree()->nextSibling()) {
+    for (Frame* child = frame()->tree().firstChild(); child; child = child->tree().nextSibling()) {
         Document* childDocument = child->document();
         if (childDocument->shouldDisplaySeamlesslyWithParent()) {
             ASSERT(childDocument->seamlessParentIFrame()->document() == this);
@@ -4118,7 +4118,7 @@ KURL Document::openSearchDescriptionURL()
     static const char* const openSearchRelation = "search";
 
     // FIXME: Why do only top-level frames have openSearchDescriptionURLs?
-    if (!frame() || frame()->tree()->parent())
+    if (!frame() || frame()->tree().parent())
         return KURL();
 
     // FIXME: Why do we need to wait for FrameStateComplete?
@@ -4180,7 +4180,7 @@ void Document::setTransformSource(PassOwnPtr<TransformSource> source)
 void Document::setDesignMode(InheritedBool value)
 {
     m_designMode = value;
-    for (Frame* frame = m_frame; frame && frame->document(); frame = frame->tree()->traverseNext(m_frame))
+    for (Frame* frame = m_frame; frame && frame->document(); frame = frame->tree().traverseNext(m_frame))
         frame->document()->setNeedsStyleRecalc();
 }
 
@@ -4202,7 +4202,7 @@ Document* Document::parentDocument() const
 {
     if (!m_frame)
         return 0;
-    Frame* parent = m_frame->tree()->parent();
+    Frame* parent = m_frame->tree().parent();
     if (!parent)
         return 0;
     return parent->document();
@@ -4536,8 +4536,8 @@ void Document::initSecurityContext(const DocumentInit& initializer)
 
 void Document::initContentSecurityPolicy(const ContentSecurityPolicyResponseHeaders& headers)
 {
-    if (m_frame && m_frame->tree()->parent() && (shouldInheritSecurityOriginFromOwner(m_url) || isPluginDocument()))
-        contentSecurityPolicy()->copyStateFrom(m_frame->tree()->parent()->document()->contentSecurityPolicy());
+    if (m_frame && m_frame->tree().parent() && (shouldInheritSecurityOriginFromOwner(m_url) || isPluginDocument()))
+        contentSecurityPolicy()->copyStateFrom(m_frame->tree().parent()->document()->contentSecurityPolicy());
     contentSecurityPolicy()->didReceiveHeaders(headers);
 }
 
@@ -4974,7 +4974,7 @@ void Document::didRemoveTouchEventHandler(Node* handler)
         scrollingCoordinator->touchEventTargetRectsDidChange(this);
     if (m_touchEventTargets->size())
         return;
-    for (const Frame* frame = page->mainFrame(); frame; frame = frame->tree()->traverseNext()) {
+    for (const Frame* frame = page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
         if (frame->document() && frame->document()->hasTouchEventHandlers())
             return;
     }