Bug 584703. Compute XUL listbox contents overlow area correctly. r=enndeakin

--HG--
extra : rebase_source : a5c20c7ad240643a734a3e0f27c5357adc13c9ae

layout/xul/base/src/nsListBoxBodyFrame.cpp

@@ -290,6 +290,24 @@ nsListBoxBodyFrame::DoLayout(nsBoxLayoutState& aBoxLayoutState)
 
   nsresult rv = nsBoxFrame::DoLayout(aBoxLayoutState);
 
+  // determine the real height for the scrollable area from the total number
+  // of rows, since non-visible rows don't yet have frames
+  nsSize size = GetSize();
+  nsRect overflowRect = nsRect(nsPoint(0, 0), size);
+  if (mLayoutManager) {
+    nsIFrame* childFrame = mFrames.FirstChild();
+    while (childFrame) {
+      ConsiderChildOverflow(overflowRect, childFrame);
+      childFrame = childFrame->GetNextSibling();
+    }
+
+    nsSize prefSize = mLayoutManager->GetPrefSize(this, aBoxLayoutState);
+    if (prefSize.height > overflowRect.height) {
+      overflowRect.height = prefSize.height;
+    }
+  }
+  FinishAndStoreOverflow(&overflowRect, GetSize());
+
   if (mScrolling)
     aBoxLayoutState.SetPaintingDisabled(PR_FALSE);
 

layout/xul/base/src/nsListBoxBodyFrame.h

@@ -156,6 +156,8 @@ public:
 
   virtual PRBool SupportsOrdinalsInChildren();
 
+  virtual PRBool ComputesOwnOverflowArea() { return PR_TRUE; }
+
 protected:
   class nsPositionChangedEvent;
   friend class nsPositionChangedEvent;

toolkit/content/tests/widgets/test_hiddenpaging.xul

@@ -104,6 +104,8 @@ function testListbox()
   ok(listbox.firstChild.getBoundingClientRect().width < listbox.getBoundingClientRect().width - 10,
      id + ": Scrollbar visible");
 
+  var rowHeight = listbox.firstChild.getBoundingClientRect().height;
+
   listbox.selectedIndex = 0;
   sendKey("PAGE_DOWN", id);
   is(listbox.selectedItem.id, id + "_item8", id + ": Page down should go to the item one visible page away");
@@ -124,6 +126,27 @@ function testListbox()
   sendKey("PAGE_UP", id);
   is(listbox.selectedItem.id, id + "_item1", id + ": Third page up should return to the first visible item");
   is(listbox.getIndexOfFirstVisibleRow(), 0, id + ": Third page up should not have scrolled at all");
+
+  var scrollHeight = document.getAnonymousNodes(listbox)[1].lastChild.scrollHeight;
+  is(scrollHeight, rowHeight * 15, id + ": scrollHeight when rows set");
+
+  listbox.minHeight = 50;
+  scrollHeight = document.getAnonymousNodes(listbox)[1].lastChild.scrollHeight;
+  is(scrollHeight, rowHeight * 15, id + ": scrollHeight when rows and minimium height set");
+
+  listbox.removeAttribute("rows");
+
+  var availHeight = document.getAnonymousNodes(listbox)[1].lastChild.getBoundingClientRect().height;
+  // The listbox layout adds this extra height in GetPrefSize. Not sure what it's for though.
+  var e = (rowHeight * 15 - availHeight) % rowHeight;
+  var extraHeight = (e == 0) ? 0 : rowHeight - e;
+
+  scrollHeight = document.getAnonymousNodes(listbox)[1].lastChild.scrollHeight;
+  is(scrollHeight, rowHeight * 15 + extraHeight, id + ": scrollHeight when minimium height set");
+
+  listbox.removeAttribute("minheight");
+  scrollHeight = document.getAnonymousNodes(listbox)[1].lastChild.scrollHeight;
+  is(scrollHeight, rowHeight * 15 + extraHeight, id + ": scrollHeight");
 }
 
 window.onload = function runTests() {