Revert "Move some scroll invalidations to the paint invalidation phase"

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 1326 matching lines @@
 
     for (RenderLayer* child = layer->firstChild(); child; child = child->nextSibling()) {
         // Don't include paint invalidation rects for composited child layers; they will paint themselves and have a different origin.
         if (child->isPaintInvalidationContainer())
             continue;
 
         setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants(child);
     }
 }
 
+LayoutRect paintInvalidationRectIncludingNonCompositingDescendants(RenderLayer* layer)
+{
+    LayoutRect paintInvalidationRect = layer->renderer()->previousPaintInvalidationRect();
+    for (RenderLayer* child = layer->firstChild(); child; child = child->nextSibling()) {
+        // Don't include paint invalidation rects for composited child layers; they will paint themselves and have a different origin.
+        if (child->isPaintInvalidationContainer())
+            continue;
+
+        paintInvalidationRect.unite(paintInvalidationRectIncludingNonCompositingDescendants(child));
+    }
+    return paintInvalidationRect;
+}
+
 bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta)
 {
     if (!contentsInCompositedLayer() || hasSlowRepaintObjects())
         return false;
 
     if (!m_viewportConstrainedObjects || m_viewportConstrainedObjects->isEmpty()) {
         InspectorInstrumentation::didScroll(page());
         return true;
     }
 
+    Region regionToUpdate;
     for (const auto& viewportConstrainedObject : *m_viewportConstrainedObjects) {
         RenderObject* renderer = viewportConstrainedObject;
         ASSERT(renderer->style()->hasViewportConstrainedPosition());
         ASSERT(renderer->hasLayer());
         RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
 
         if (layer->isPaintInvalidationContainer())
             continue;
 
         if (layer->subtreeIsInvisible())
             continue;
 
         // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
         // scroll using the fast path, otherwise the outsets of the filter will be moved around the page.
         if (layer->hasAncestorWithFilterOutsets())
             return false;
 
-        setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants(layer);
+        IntRect updateRect = pixelSnappedIntRect(paintInvalidationRectIncludingNonCompositingDescendants(layer));
+
+        const RenderLayerModelObject* repaintContainer = layer->renderer()->containerForPaintInvalidation();
+        if (repaintContainer && !repaintContainer->isRenderView()) {
+            // Invalidate the old and new locations of fixed position elements that are not drawn into the RenderView.
+            updateRect.moveBy(scrollPosition());
+            IntRect previousRect = updateRect;
+            previousRect.move(scrollDelta);
+            // FIXME: Rather than uniting the rects, we should just issue both invalidations.
+            updateRect.unite(previousRect);
+            layer->renderer()->invalidatePaintUsingContainer(repaintContainer, updateRect, PaintInvalidationScroll);
+        } else {
+            // Coalesce the paint invalidations that will be issued to the renderView.
+            updateRect = contentsToRootView(updateRect);
+            if (!updateRect.isEmpty())
+                regionToUpdate.unite(updateRect);
+        }
     }
 
     InspectorInstrumentation::didScroll(page());
+
+    // Invalidate the old and new locations of fixed position elements that are drawn into the RenderView.
+    Vector<IntRect> subRectsToUpdate = regionToUpdate.rects();
+    size_t viewportConstrainedObjectsCount = subRectsToUpdate.size();
+    for (size_t i = 0; i < viewportConstrainedObjectsCount; ++i) {
+        IntRect updateRect = subRectsToUpdate[i];
+        IntRect scrolledRect = updateRect;
+        scrolledRect.move(-scrollDelta);
+        updateRect.unite(scrolledRect);
+        // FIXME: We should be able to issue these invalidations separately and before we actually scroll.
+        renderView()->setBackingNeedsPaintInvalidationInRect(rootViewToContents(updateRect), PaintInvalidationScroll);
+    }
+
     return true;
 }
 
 void FrameView::scrollContentsSlowPath(const IntRect& updateRect)
 {
     if (contentsInCompositedLayer()) {
         IntRect updateRect = visibleContentRect();
         ASSERT(renderView());
         renderView()->invalidatePaintRectangle(updateRect);
     }
@@ skipping 1159 matching lines @@
         InspectorInstrumentation::willUpdateLayerTree(m_frame.get());
 
         view->compositor()->updateIfNeededRecursive();
 
         if (view->compositor()->inCompositingMode() && m_frame->isLocalRoot())
             m_frame->page()->scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
 
         updateCompositedSelectionBoundsIfNeeded();
 
         InspectorInstrumentation::didUpdateLayerTree(m_frame.get());
+
+        scrollContentsIfNeededRecursive();
+
+        invalidateTreeIfNeededRecursive();
     }
 
-    scrollContentsIfNeededRecursive();
-
-    if (view)
-        invalidateTreeIfNeededRecursive();
-
     ASSERT(lifecycle().state() == DocumentLifecycle::PaintInvalidationClean);
 }
 
 void FrameView::updateLayoutAndStyleIfNeededRecursive()
 {
     // We have to crawl our entire tree looking for any FrameViews that need
     // layout and make sure they are up to date.
     // Mac actually tests for intersection with the dirty region and tries not to
     // update layout for frames that are outside the dirty region.  Not only does this seem
     // pointless (since those frames will have set a zero timer to layout anyway), but
@@ skipping 1384 matching lines @@
         return;
 
     ScrollableArea::setScrollOrigin(origin);
 
     // Update if the scroll origin changes, since our position will be different if the content size did not change.
     if (updatePositionAtAll && updatePositionSynchronously)
         updateScrollbars(scrollOffsetDouble());
 }
 
 } // namespace blink