Remove updatePaintingInfoForFragments() and per-fragment shouldPaintContent flag.

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index ba9c9160db2976b1d391d06894bc2f66cab7d88d..0dc7d9056e22e0fe860d3f75a7812b87ae2b8bee 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -1468,9 +1468,7 @@ 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.
@@ -1480,6 +1478,8 @@ void RenderLayer::collectFragments(LayerFragments& fragments, const RenderLayer*
             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;
     }
 
@@ -1523,8 +1523,11 @@ void RenderLayer::collectFragments(LayerFragments& fragments, const RenderLayer*
     // 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;
@@ -1553,6 +1556,8 @@ void RenderLayer::collectFragments(LayerFragments& fragments, const RenderLayer*
         // 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)
@@ -1798,7 +1803,7 @@ RenderLayer* RenderLayer::hitTestLayer(RenderLayer* rootLayer, RenderLayer* cont
 
     // 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());
@@ -1882,7 +1887,7 @@ RenderLayer* RenderLayer::hitTestTransformedLayerInFragments(RenderLayer* rootLa
     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) {