Remove updatePaintingInfoForFragments() and per-fragment shouldPaintContent flag.

Source/core/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 1450 matching lines @@
         m_scrollableArea = adoptPtr(new RenderLayerScrollableArea(*this));
     else
         m_scrollableArea = nullptr;
 }
 
 bool RenderLayer::hasOverflowControls() const
 {
     return m_scrollableArea && (m_scrollableArea->hasScrollbar() || m_scrollableArea->hasScrollCorner() || renderer()->style()->resize() != RESIZE_NONE);
 }
 
-void RenderLayer::collectFragments(LayerFragments& fragments, const RenderLayer* rootLayer, const LayoutRect& dirtyRect,
-    ClipRectsCacheSlot clipRectsCacheSlot, OverlayScrollbarSizeRelevancy inOverlayScrollbarSizeRelevancy, ShouldRespectOverflowClip respectOverflowClip, const LayoutPoint* offsetFromRoot,
-    const LayoutSize& subPixelAccumulation, const LayoutRect* layerBoundingBox)
+void RenderLayer::collectFragments(LayerFragments& fragments, DirtyRectIntersectionResult* intersectionResult, const RenderLayer* rootLayer, const LayoutRect& dirtyRect, ClipRectsCacheSlot clipRectsCacheSlot, OverlayScrollbarSizeRelevancy inOverlayScrollbarSizeRelevancy, ShouldRespectOverflowClip respectOverflowClip, const LayoutPoint* offsetFromRoot, const LayoutSize& subPixelAccumulation, const LayoutRect* layerBoundingBox)
 {
     if (!enclosingPaginationLayer() || hasTransformRelatedProperty()) {
         // For unpaginated layers, there is only one fragment.
         LayerFragment fragment;
         ClipRectsContext clipRectsContext(rootLayer, clipRectsCacheSlot, inOverlayScrollbarSizeRelevancy, subPixelAccumulation);
         if (respectOverflowClip == IgnoreOverflowClip)
             clipRectsContext.setIgnoreOverflowClip();
         clipper().calculateRects(clipRectsContext, dirtyRect, fragment.layerBounds, fragment.backgroundRect, fragment.foregroundRect, fragment.outlineRect, offsetFromRoot);
         fragments.append(fragment);
+        if (intersectionResult)
+            *intersectionResult = intersectsDamageRect(fragment.layerBounds, fragment.backgroundRect.rect(), rootLayer, offsetFromRoot) ? IntersectingDirtyRect : NotIntersectingDirtyRect;
         return;
     }
 
     // Compute our offset within the enclosing pagination layer.
     LayoutPoint offsetWithinPaginatedLayer;
     convertToLayerCoords(enclosingPaginationLayer(), offsetWithinPaginatedLayer);
 
     // Calculate clip rects relative to the enclosingPaginationLayer. The purpose of this call is to determine our bounds clipped to intermediate
     // layers between us and the pagination context. It's important to minimize the number of fragments we need to create and this helps with that.
     ClipRectsContext paginationClipRectsContext(enclosingPaginationLayer(), clipRectsCacheSlot, inOverlayScrollbarSizeRelevancy);
@@ skipping 23 matching lines @@
     } else {
         enclosingPaginationLayer()->convertToLayerCoords(rootLayer, offsetOfPaginationLayerFromRoot);
     }
     LayoutRect dirtyRectInFlowThread(dirtyRect);
     dirtyRectInFlowThread.moveBy(-offsetOfPaginationLayerFromRoot);
 
     // Tell the flow thread to collect the fragments. We pass enough information to create a minimal number of fragments based off the pages/columns
     // that intersect the actual dirtyRect as well as the pages/columns that intersect our layer's bounding box.
     enclosingFlowThread->collectLayerFragments(fragments, layerBoundingBoxInFlowThread, dirtyRectInFlowThread);
 
-    if (fragments.isEmpty())
+    if (fragments.isEmpty()) {

[chrishtr, 2014/10/28 18:47:42]

When would there ever be 0 fragments? Will this part of the method only be
reachable for columns?

[chrishtr, 2014/10/28 18:47:42]

When would there ever be 0 fragments?

[mstensho (USE GERRIT), 2014/10/28 20:08:21]

Yes, only reachable by columns. There'll be no fragments if none of the columns
intersect with the damage rect, for instance.

+        if (intersectionResult)
+            *intersectionResult = NotIntersectingDirtyRect;
         return;
+    }
 
     // Get the parent clip rects of the pagination layer, since we need to intersect with that when painting column contents.
     ClipRect ancestorClipRect = dirtyRect;
     if (enclosingPaginationLayer()->parent()) {
         ClipRectsContext clipRectsContext(rootLayer, clipRectsCacheSlot, inOverlayScrollbarSizeRelevancy);
         if (respectOverflowClip == IgnoreOverflowClip)
             clipRectsContext.setIgnoreOverflowClip();
         ancestorClipRect = enclosingPaginationLayer()->clipper().backgroundClipRect(clipRectsContext);
         ancestorClipRect.intersect(dirtyRect);
     }
 
     for (size_t i = 0; i < fragments.size(); ++i) {
         LayerFragment& fragment = fragments.at(i);
 
         // Set our four rects with all clipping applied that was internal to the flow thread.
         fragment.setRects(layerBoundsInFlowThread, backgroundRectInFlowThread, foregroundRectInFlowThread, outlineRectInFlowThread);
 
         // Shift to the root-relative physical position used when painting the flow thread in this fragment.
         fragment.moveBy(fragment.paginationOffset + offsetOfPaginationLayerFromRoot);
 
         // Intersect the fragment with our ancestor's background clip so that e.g., columns in an overflow:hidden block are
         // properly clipped by the overflow.
         fragment.intersect(ancestorClipRect.rect());
 
         // Now intersect with our pagination clip. This will typically mean we're just intersecting the dirty rect with the column
         // clip, so the column clip ends up being all we apply.
         fragment.intersect(fragment.paginationClip);
     }
+    if (intersectionResult)
+        *intersectionResult = IntersectingDirtyRect;
 }
 
 static inline LayoutRect frameVisibleRect(RenderObject* renderer)
 {
     FrameView* frameView = renderer->document().view();
     if (!frameView)
         return LayoutRect();
 
     return frameView->visibleContentRect();
 }
@@ skipping 225 matching lines @@
     hitLayer = hitTestChildren(NormalFlowChildren, rootLayer, request, result, hitTestRect, hitTestLocation,
                            localTransformState.get(), zOffsetForDescendantsPtr, zOffset, unflattenedTransformState.get(), depthSortDescendants);
     if (hitLayer) {
         if (!depthSortDescendants)
             return hitLayer;
         candidateLayer = hitLayer;
     }
 
     // Collect the fragments. This will compute the clip rectangles for each layer fragment.
     LayerFragments layerFragments;
-    collectFragments(layerFragments, rootLayer, hitTestRect, RootRelativeClipRects, IncludeOverlayScrollbarSize);
+    collectFragments(layerFragments, 0, rootLayer, hitTestRect, RootRelativeClipRects, IncludeOverlayScrollbarSize);
 
     if (m_scrollableArea && m_scrollableArea->hitTestResizerInFragments(layerFragments, hitTestLocation)) {
         renderer()->updateHitTestResult(result, hitTestLocation.point());
         return this;
     }
 
     // Next we want to see if the mouse pos is inside the child RenderObjects of the layer. Check
     // every fragment in reverse order.
     if (isSelfPaintingLayer()) {
         // Hit test with a temporary HitTestResult, because we only want to commit to 'result' if we know we're frontmost.
@@ skipping 63 matching lines @@
     return false;
 }
 
 RenderLayer* RenderLayer::hitTestTransformedLayerInFragments(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest& request, HitTestResult& result,
     const LayoutRect& hitTestRect, const HitTestLocation& hitTestLocation, const HitTestingTransformState* transformState, double* zOffset)
 {
     LayerFragments enclosingPaginationFragments;
     LayoutPoint offsetOfPaginationLayerFromRoot;
     // FIXME: We're missing a sub-pixel offset here crbug.com/348728
     LayoutRect transformedExtent = transparencyClipBox(this, enclosingPaginationLayer(), HitTestingTransparencyClipBox, RenderLayer::RootOfTransparencyClipBox, LayoutSize());
-    enclosingPaginationLayer()->collectFragments(enclosingPaginationFragments, rootLayer, hitTestRect,
+    enclosingPaginationLayer()->collectFragments(enclosingPaginationFragments, 0, rootLayer, hitTestRect,
         RootRelativeClipRects, IncludeOverlayScrollbarSize, RespectOverflowClip, &offsetOfPaginationLayerFromRoot, LayoutSize(), &transformedExtent);
 
     for (int i = enclosingPaginationFragments.size() - 1; i >= 0; --i) {
         const LayerFragment& fragment = enclosingPaginationFragments.at(i);
 
         // Apply the page/column clip for this fragment, as well as any clips established by layers in between us and
         // the enclosing pagination layer.
         LayoutRect clipRect = fragment.backgroundRect.rect();
 
         // Now compute the clips within a given fragment
@@ skipping 974 matching lines @@
     }
 }
 
 void showLayerTree(const blink::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif