Add background attachment fixed main thread scrolling reason [spv2]

third_party/WebKit/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 1328 matching lines @@
     return !layoutViewItem.isNull() && layoutViewItem.compositingState() == PaintsIntoOwnBacking;
 }
 
 void FrameView::addBackgroundAttachmentFixedObject(LayoutObject* object)
 {
     ASSERT(!m_backgroundAttachmentFixedObjects.contains(object));
 
     m_backgroundAttachmentFixedObjects.add(object);
     if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
         scrollingCoordinator->frameViewHasBackgroundAttachmentFixedObjectsDidChange(this);
+
+    // TODO(pdr): When slimming paint v2 is enabled, invalidate the scroll paint
+    // property subtree for this so main thread scroll reasons are recomputed.
 }
 
 void FrameView::removeBackgroundAttachmentFixedObject(LayoutObject* object)
 {
     ASSERT(m_backgroundAttachmentFixedObjects.contains(object));
 
     m_backgroundAttachmentFixedObjects.remove(object);
     if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
         scrollingCoordinator->frameViewHasBackgroundAttachmentFixedObjectsDidChange(this);
+
+    // TODO(pdr): When slimming paint v2 is enabled, invalidate the scroll paint
+    // property subtree for this so main thread scroll reasons are recomputed.
 }
 
 void FrameView::addViewportConstrainedObject(LayoutObject* object)
 {
     if (!m_viewportConstrainedObjects)
         m_viewportConstrainedObjects = wrapUnique(new ViewportConstrainedObjectSet);
 
     if (!m_viewportConstrainedObjects->contains(object)) {
         m_viewportConstrainedObjects->add(object);
 
@@ skipping 2989 matching lines @@
 }
 
 bool FrameView::canThrottleRendering() const
 {
     if (!RuntimeEnabledFeatures::renderingPipelineThrottlingEnabled())
         return false;
     return m_subtreeThrottled || (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
 } // namespace blink