Layout overflow from transforms should update frame scrollbars

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 620 matching lines @@
 
 void FrameView::recalcOverflowAfterStyleChange()
 {
     RenderView* renderView = this->renderView();
     ASSERT(renderView);
     if (!renderView->needsOverflowRecalcAfterStyleChange())
         return;
 
     renderView->recalcOverflowAfterStyleChange();
 
-    // FIXME: We should adjust frame scrollbar here, but that will make many
-    // tests flake in debug build.
+    if (needsLayout())
+        return;
+
+    InUpdateScrollbarsScope inUpdateScrollbarsScope(this);
+
+    bool shouldHaveHorizontalScrollbar = false;
+    bool shouldHaveVerticalScrollbar = false;
+    computeScrollbarExistence(shouldHaveHorizontalScrollbar, shouldHaveVerticalScrollbar);
+
+    bool hasHorizontalScrollbar = horizontalScrollbar();
+    bool hasVerticalScrollbar = verticalScrollbar();
+    if (hasHorizontalScrollbar != shouldHaveHorizontalScrollbar
+        || hasVerticalScrollbar != shouldHaveVerticalScrollbar) {
+        setNeedsLayout();
+        return;
+    }
+
+    adjustViewSize();
+    updateScrollbarGeometry();
 }
 
 bool FrameView::usesCompositedScrolling() const
 {
     RenderView* renderView = this->renderView();
     if (!renderView)
         return false;
     if (m_frame->settings() && m_frame->settings()->compositedScrollingForFramesEnabled())
         return renderView->compositor()->inCompositingMode();
     return false;
@@ skipping 2625 matching lines @@
 void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
     ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
     if (AXObjectCache* cache = axObjectCache()) {
         cache->remove(scrollbar);
         cache->handleScrollbarUpdate(this);
     }
 }
 
 } // namespace WebCore