Bug 226155 DRefTool analysis for accessible files

r=roc sr=roc

accessible/src/atk/nsAccessibleHyperText.cpp

@@ -505,6 +505,9 @@ nsresult nsAccessibleHyperText::GetBounds(nsIWeakReference *aWeakShell, PRInt32
   for (index = 0; index < count; index++) {
     nsHTMLTextAccessible *accText = new nsHTMLTextAccessible(
         (nsIDOMNode *)mTextChildren->ElementAt(index), aWeakShell);
+    if (!accText)
+      return NS_ERROR_OUT_OF_MEMORY;
+
     nsRect frameRect;
     accText->GetBounds(&frameRect.x, &frameRect.y, &frameRect.width, &frameRect.height);
     unionRectTwips.UnionRect(unionRectTwips, frameRect);

accessible/src/base/nsAccessibilityService.cpp

@@ -314,6 +314,8 @@ nsAccessibilityService::CreateRootAccessible(nsIPresShell *aShell,
   else {
     *aRootAcc = new nsRootAccessibleWrap(rootNode, weakShell);
   }
+  if (!*aRootAcc)
+    return NS_ERROR_OUT_OF_MEMORY;
 
   nsCOMPtr<nsPIAccessNode> privateAccessNode(do_QueryInterface(*aRootAcc));
   privateAccessNode->Init();

accessible/src/msaa/nsAccessNodeWrap.cpp

@@ -406,6 +406,9 @@ ISimpleDOMNode* nsAccessNodeWrap::MakeAccessNode(nsIDOMNode *node)
   }
   else {
     newNode = new nsAccessNodeWrap(node, mWeakShell);
+    if (!newNode)
+      return NULL;
+
     newNode->Init();
     iNode = NS_STATIC_CAST(ISimpleDOMNode*, newNode);
     iNode->AddRef();