Bug 547342 real fix. Flush on ScrollToRow. r=enn

content/xul/templates/tests/test_bug441785.xul

@@ -107,7 +107,6 @@ var oldtreefirstrow, oldtreecfirstrow;
 
 function nextDataSource()
 {
-  document.documentElement.getBoundingClientRect();
   var tree = document.getElementById('t');
   var treec = document.getElementById('tc');
   tree.treeBoxObject.scrollToRow(10);

layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp

@@ -143,6 +143,7 @@ nsTreeBodyFrame::nsTreeBodyFrame(nsIPresShell* aPresShell, nsStyleContext* aCont
 :nsLeafBoxFrame(aPresShell, aContext),
  mSlots(nsnull),
  mTopRowIndex(0),
+ mPageLength(0),
  mHorzPosition(0),
  mHorzWidth(0),
  mAdjustWidth(0),

layout/xul/base/src/tree/src/nsTreeBoxObject.cpp

@@ -114,13 +114,13 @@ static void FindBodyElement(nsIContent* aParent, nsIContent** aResult)
 }
 
 nsTreeBodyFrame*
-nsTreeBoxObject::GetTreeBody()
+nsTreeBoxObject::GetTreeBody(bool aFlushLayout)
 {
   if (mTreeBody) {
     return mTreeBody;
   }
 
-  nsIFrame* frame = GetFrame(PR_FALSE);
+  nsIFrame* frame = GetFrame(aFlushLayout);
   if (!frame)
     return nsnull;
 
@@ -324,7 +324,7 @@ nsTreeBoxObject::EnsureCellIsVisible(PRInt32 aRow, nsITreeColumn* aCol)
 NS_IMETHODIMP
 nsTreeBoxObject::ScrollToRow(PRInt32 aRow)
 {
-  nsTreeBodyFrame* body = GetTreeBody();
+  nsTreeBodyFrame* body = GetTreeBody(true);
   if (body)
     return body->ScrollToRow(aRow);
   return NS_OK;

layout/xul/base/src/tree/src/nsTreeBoxObject.h

@@ -57,7 +57,7 @@ public:
   nsTreeBoxObject();
   ~nsTreeBoxObject();
 
-  nsTreeBodyFrame* GetTreeBody();
+  nsTreeBodyFrame* GetTreeBody(bool aFlushLayout = false);
   nsTreeBodyFrame* GetCachedTreeBody() { return mTreeBody; }
 
   //NS_PIBOXOBJECT interfaces