Bug 339548. Part 7: Create nsLayoutUtils::IsAncestorFrameCrossDoc. r=dbaron

layout/base/nsLayoutUtils.cpp

@@ -317,6 +317,16 @@ nsLayoutUtils::IsProperAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame*
   return PR_FALSE;
 }
 
+// static
+PRBool
+nsLayoutUtils::IsAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
+                                       nsIFrame* aCommonAncestor)
+{
+  if (aFrame == aAncestorFrame)
+    return PR_TRUE;
+  return IsProperAncestorFrameCrossDoc(aAncestorFrame, aFrame, aCommonAncestor);
+}
+
 // static
 PRBool
 nsLayoutUtils::IsProperAncestorFrame(nsIFrame* aAncestorFrame, nsIFrame* aFrame,

layout/base/nsLayoutUtils.h

@@ -251,10 +251,26 @@ public:
 
   /**
    * Like IsProperAncestorFrame, but looks across document boundaries.
+   *
+   * Just like IsAncestorFrameCrossDoc, except that it returns false when
+   * aFrame == aAncestorFrame.
    */
   static PRBool IsProperAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
                                               nsIFrame* aCommonAncestor = nsnull);
 
+  /**
+   * IsAncestorFrameCrossDoc checks whether aAncestorFrame is an ancestor
+   * of aFrame or equal to aFrame, looking across document boundaries.
+   * @param aCommonAncestor nsnull, or a common ancestor of aFrame and
+   * aAncestorFrame. If non-null, this can bound the search and speed up
+   * the function.
+   *
+   * Just like IsProperAncestorFrameCrossDoc, except that it returns true when
+   * aFrame == aAncestorFrame.
+   */
+  static PRBool IsAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
+                                        nsIFrame* aCommonAncestor = nsnull);
+
   /**
     * GetFrameFor returns the root frame for a view
     * @param aView is the view to return the root frame for