Bug 218832 [W] UMR: Uninitialized memory read in nsView::ConvertToParentCoords(int *,int *)const

r=roc sr=roc

view/src/nsScrollPortView.cpp

@@ -382,7 +382,10 @@ void nsScrollPortView::AdjustChildWidgets(nsScrollPortView *aScrolling, nsView *
   if (aScrolling == aView)
   {
     nsIWidget *widget;
-    aScrolling->GetOffsetFromWidget(&aDx, &aDy, widget);
+    nscoord dx, dy;
+    aScrolling->GetOffsetFromWidget(&dx, &dy, widget);
+    aDx += dx;
+    aDy += dy;
     NS_IF_RELEASE(widget);
   }
 

view/src/nsView.cpp

@@ -883,22 +883,25 @@ NS_IMETHODIMP nsView::GetOffsetFromWidget(nscoord *aDx, nscoord *aDy, nsIWidget
   nsView   *ancestor = GetParent();
   aWidget = nsnull;
   
-  // XXX aDx and aDy are OUT parameters and so we should initialize them
-  // to 0 rather than relying on the caller to do so...
-  while (nsnull != ancestor)
+  if (aDx) *aDx = 0;
+  if (aDy) *aDy = 0;
+  while (ancestor)
   {
     aWidget = ancestor->GetWidget();
     if (aWidget) {
       NS_ADDREF(aWidget);
       // the widget's (0,0) is at the top left of the view's bounds, NOT its position
+      if (aDx && aDy)
+      {
         nsRect r;
         ancestor->GetDimensions(r);
-      aDx -= r.x;
-      aDy -= r.y;
+        *aDx -= r.x;
+        *aDy -= r.y;
+      }
       return NS_OK;
     }
 
-    if ((nsnull != aDx) && (nsnull != aDy))
+    if (aDx && aDy)
     {
       ancestor->ConvertToParentCoords(aDx, aDy);
     }