Bug 312788. Crash when exposing plugins with width or height of 0. r=parente, sr=bryner

accessible/src/base/nsAccessibilityService.cpp

@@ -718,6 +718,10 @@ nsAccessibilityService::CreateHTMLObjectFrameAccessible(nsObjectFrame *aFrame,
   nsIFrame *frame;
   GetInfo(NS_STATIC_CAST(nsIFrame*, aFrame), &frame, getter_AddRefs(weakShell), getter_AddRefs(node));
 
+  *aAccessible = nsnull;
+  if (!frame || frame->GetRect().IsEmpty()) {
+    return NS_ERROR_FAILURE;
+  }
   // 1) for object elements containing either HTML or TXT documents
   nsCOMPtr<nsIDOMDocument> domDoc;
   nsCOMPtr<nsIDOMHTMLObjectElement> obj(do_QueryInterface(node));

accessible/src/msaa/nsHTMLWin32ObjectAccessible.cpp

@@ -85,7 +85,7 @@ NS_IMETHODIMP nsHTMLWin32ObjectOwnerAccessible::GetChildCount(PRInt32 *aChildCou
 }
 
 nsHTMLWin32ObjectAccessible::nsHTMLWin32ObjectAccessible(void* aHwnd):
-nsAccessibleWrap(nsnull, nsnull)
+nsLeafAccessible(nsnull, nsnull)
 {
   mHwnd = aHwnd;
   if (mHwnd) {

accessible/src/msaa/nsHTMLWin32ObjectAccessible.h

@@ -40,7 +40,7 @@
 #define _nsHTMLWin32ObjectAccessible_H_
 
 #include "nsIAccessibleWin32Object.h"
-#include "nsAccessibleWrap.h"
+#include "nsBaseWidgetAccessible.h"
 
 struct IAccessible;
 
@@ -74,7 +74,7 @@ protected:
   *   object returned by us in Accessible::NewAccessible() that gets the IAccessible
   *   from the windows system from the window handle.
   */
-class nsHTMLWin32ObjectAccessible : public nsAccessibleWrap,
+class nsHTMLWin32ObjectAccessible : public nsLeafAccessible,
                                     public nsIAccessibleWin32Object
 {
 public: