Implement incremental paint property tree rebuilding

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 166 matching lines @@
       m_verticalScrollbarMode(ScrollbarAuto),
       m_horizontalScrollbarLock(false),
       m_verticalScrollbarLock(false),
       m_scrollbarsSuppressed(false),
       m_inUpdateScrollbars(false),
       m_frameTimingRequestsDirty(true),
       m_viewportIntersectionValid(false),
       m_hiddenForThrottling(false),
       m_crossOriginForThrottling(false),
       m_subtreeThrottled(false),
+      m_needsPaintPropertyUpdate(true),
       m_currentUpdateLifecyclePhasesTargetState(
           DocumentLifecycle::Uninitialized),
       m_scrollAnchor(this),
       m_scrollbarManager(*this),
       m_needsScrollbarsUpdate(false),
       m_suppressAdjustViewSize(false),
       m_allowsLayoutInvalidationAfterLayoutClean(true) {
   ASSERT(m_frame);
   init();
 }
@@ skipping 402 matching lines @@
   ScrollableArea::contentsResized();
 
   Page* page = frame().page();
   if (!page)
     return;
 
   updateScrollableAreaSet();
 
   page->chromeClient().contentsSizeChanged(m_frame.get(), size);
   frame().loader().restoreScrollPositionAndViewState();
+
+  if (!RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    // The presence of overflow depends on the contents size. The scroll
+    // properties can change depending on whether overflow scrolling occurs.
+    setNeedsPaintPropertyUpdate();
+  }
 }
 
 void FrameView::adjustViewSize() {
   if (m_suppressAdjustViewSize)
     return;
 
   LayoutViewItem layoutViewItem = this->layoutViewItem();
   if (layoutViewItem.isNull())
     return;
 
@@ skipping 3012 matching lines @@
   }
 
   if (scrollType != AnchoringScroll)
     clearScrollAnchor();
 }
 
 void FrameView::didChangeScrollOffset() {
   frame().loader().client()->didChangeScrollOffset();
   if (frame().isMainFrame())
     frame().host()->chromeClient().mainFrameScrollOffsetChanged();
+
+  if (!RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
+    // The scroll translation paint property depends on scroll offset.
+    setNeedsPaintPropertyUpdate();
+  }
 }
 
 void FrameView::clearScrollAnchor() {
   if (!RuntimeEnabledFeatures::scrollAnchoringEnabled())
     return;
   m_scrollAnchor.clear();
 }
 
 bool FrameView::hasOverlayScrollbars() const {
   return (horizontalScrollbar() &&
@@ skipping 879 matching lines @@
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.width();
 }
 
 int FrameView::initialViewportHeight() const {
   DCHECK(m_frame->isMainFrame());
   return m_initialViewportSize.height();
 }
 
 }  // namespace blink