[SPInvalidation] Use GeometryMapper in PaintLayerClipper for paint.

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index 786449fb35c9431719650de6bd0a451cddff4080..6a5712e254c9447361c49242962e7727baeb508a 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -280,7 +280,7 @@ void PaintLayer::updateLayerPositionsAfterLayout() {
   TRACE_EVENT0("blink,benchmark",
                "PaintLayer::updateLayerPositionsAfterLayout");
 
-  clipper().clearClipRectsIncludingDescendants();
+  clipper(false).clearClipRectsIncludingDescendants();
   updateLayerPositionRecursive();
 
   {
@@ -368,7 +368,7 @@ bool PaintLayer::scrollsWithRespectTo(const PaintLayer* other) const {
 }
 
 void PaintLayer::updateLayerPositionsAfterOverflowScroll() {
-  clipper().clearClipRectsIncludingDescendants();
+  clipper(false).clearClipRectsIncludingDescendants();
   updateLayerPositionRecursive();
 }
 
@@ -405,9 +405,9 @@ void PaintLayer::updateTransform(const ComputedStyle* oldStyle,
 
     // PaintLayers with transforms act as clip rects roots, so clear the cached
     // clip rects here.
-    clipper().clearClipRectsIncludingDescendants();
+    clipper(false).clearClipRectsIncludingDescendants();
   } else if (hasTransform) {
-    clipper().clearClipRectsIncludingDescendants(AbsoluteClipRects);
+    clipper(false).clearClipRectsIncludingDescendants(AbsoluteClipRects);
   }
 
   updateTransformationMatrix();
@@ -1329,7 +1329,7 @@ void PaintLayer::removeOnlyThisLayerAfterStyleChange() {
       enclosingSelfPaintingLayer->mergeNeedsPaintPhaseFlagsFrom(*this);
   }
 
-  clipper().clearClipRectsIncludingDescendants();
+  clipper(false).clearClipRectsIncludingDescendants();
 
   PaintLayer* nextSib = nextSibling();
 
@@ -1393,7 +1393,7 @@ void PaintLayer::insertOnlyThisLayerAfterStyleChange() {
   }
 
   // Clear out all the clip rects.
-  clipper().clearClipRectsIncludingDescendants();
+  clipper(false).clearClipRectsIncludingDescendants();
 }
 
 // Returns the layer reached on the walk up towards the ancestor.
@@ -1516,6 +1516,7 @@ void PaintLayer::appendSingleFragmentIgnoringPagination(
     const PaintLayer* rootLayer,
     const LayoutRect& dirtyRect,
     ClipRectsCacheSlot clipRectsCacheSlot,
+    bool useGeometryMapper,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
     const LayoutPoint* offsetFromRoot,
@@ -1526,9 +1527,10 @@ void PaintLayer::appendSingleFragmentIgnoringPagination(
                                     subPixelAccumulation);
   if (respectOverflowClip == IgnoreOverflowClip)
     clipRectsContext.setIgnoreOverflowClip();
-  clipper().calculateRects(clipRectsContext, dirtyRect, fragment.layerBounds,
-                           fragment.backgroundRect, fragment.foregroundRect,
-                           offsetFromRoot);
+  clipper(useGeometryMapper)
+      .calculateRects(clipRectsContext, dirtyRect, fragment.layerBounds,
+                      fragment.backgroundRect, fragment.foregroundRect,
+                      offsetFromRoot);
   fragments.push_back(fragment);
 }
 
@@ -1544,6 +1546,7 @@ void PaintLayer::collectFragments(
     const PaintLayer* rootLayer,
     const LayoutRect& dirtyRect,
     ClipRectsCacheSlot clipRectsCacheSlot,
+    bool useGeometryMapper,
     OverlayScrollbarClipBehavior overlayScrollbarClipBehavior,
     ShouldRespectOverflowClipType respectOverflowClip,
     const LayoutPoint* offsetFromRoot,
@@ -1552,7 +1555,7 @@ void PaintLayer::collectFragments(
   if (!enclosingPaginationLayer()) {
     // For unpaginated layers, there is only one fragment.
     appendSingleFragmentIgnoringPagination(
-        fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
+        fragments, rootLayer, dirtyRect, clipRectsCacheSlot, useGeometryMapper,
         overlayScrollbarClipBehavior, respectOverflowClip, offsetFromRoot,
         subPixelAccumulation);
     return;
@@ -1560,7 +1563,7 @@ void PaintLayer::collectFragments(
 
   if (!shouldFragmentCompositedBounds(rootLayer)) {
     appendSingleFragmentIgnoringPagination(
-        fragments, rootLayer, dirtyRect, clipRectsCacheSlot,
+        fragments, rootLayer, dirtyRect, clipRectsCacheSlot, useGeometryMapper,
         overlayScrollbarClipBehavior, respectOverflowClip, offsetFromRoot,
         subPixelAccumulation);
     return;
@@ -1582,10 +1585,11 @@ void PaintLayer::collectFragments(
   LayoutRect layerBoundsInFlowThread;
   ClipRect backgroundRectInFlowThread;
   ClipRect foregroundRectInFlowThread;
-  clipper().calculateRects(
-      paginationClipRectsContext, LayoutRect(LayoutRect::infiniteIntRect()),
-      layerBoundsInFlowThread, backgroundRectInFlowThread,
-      foregroundRectInFlowThread, &offsetWithinPaginatedLayer);
+  clipper(useGeometryMapper)
+      .calculateRects(paginationClipRectsContext,
+                      LayoutRect(LayoutRect::infiniteIntRect()),
+                      layerBoundsInFlowThread, backgroundRectInFlowThread,
+                      foregroundRectInFlowThread, &offsetWithinPaginatedLayer);
 
   // Take our bounding box within the flow thread and clip it.
   LayoutRect layerBoundingBoxInFlowThread =
@@ -1636,8 +1640,9 @@ void PaintLayer::collectFragments(
                                       overlayScrollbarClipBehavior);
     if (respectOverflowClip == IgnoreOverflowClip)
       clipRectsContext.setIgnoreOverflowClip();
-    ancestorClipRect = enclosingPaginationLayer()->clipper().backgroundClipRect(
-        clipRectsContext);
+    ancestorClipRect = enclosingPaginationLayer()
+                           ->clipper(useGeometryMapper)
+                           .backgroundClipRect(clipRectsContext);
     if (rootLayerIsInsidePaginationLayer)
       ancestorClipRect.moveBy(
           -rootLayer->visualOffsetFromAncestor(ancestorLayer));
@@ -1888,7 +1893,7 @@ PaintLayer* PaintLayer::hitTestLayer(
 
     // Make sure the parent's clip rects have been calculated.
     if (parent()) {
-      ClipRect clipRect = clipper().backgroundClipRect(
+      ClipRect clipRect = clipper(false).backgroundClipRect(
           ClipRectsContext(rootLayer, clipRectsCacheSlot,
                            ExcludeOverlayScrollbarSizeForHitTesting));
       // Go ahead and test the enclosing clip now.
@@ -1993,11 +1998,11 @@ PaintLayer* PaintLayer::hitTestLayer(
   PaintLayerFragments layerFragments;
   if (appliedTransform)
     appendSingleFragmentIgnoringPagination(
-        layerFragments, rootLayer, hitTestRect, clipRectsCacheSlot,
+        layerFragments, rootLayer, hitTestRect, clipRectsCacheSlot, false,
         ExcludeOverlayScrollbarSizeForHitTesting);
   else
     collectFragments(layerFragments, rootLayer, hitTestRect, clipRectsCacheSlot,
-                     ExcludeOverlayScrollbarSizeForHitTesting);
+                     false, ExcludeOverlayScrollbarSizeForHitTesting);
 
   if (m_scrollableArea &&
       m_scrollableArea->hitTestResizerInFragments(layerFragments,
@@ -2112,7 +2117,7 @@ PaintLayer* PaintLayer::hitTestTransformedLayerInFragments(
       PaintLayer::RootOfTransparencyClipBox, LayoutSize());
   enclosingPaginationLayer()->collectFragments(
       enclosingPaginationFragments, rootLayer, hitTestRect, clipRectsCacheSlot,
-      ExcludeOverlayScrollbarSizeForHitTesting, RespectOverflowClip,
+      false, ExcludeOverlayScrollbarSizeForHitTesting, RespectOverflowClip,
       &offsetOfPaginationLayerFromRoot, LayoutSize(), &transformedExtent);
 
   for (int i = enclosingPaginationFragments.size() - 1; i >= 0; --i) {
@@ -2127,7 +2132,7 @@ PaintLayer* PaintLayer::hitTestTransformedLayerInFragments(
       enclosingPaginationLayer()->convertToLayerCoords(
           rootLayer, offsetOfPaginationLayerFromRoot);
       LayoutRect parentClipRect =
-          clipper()
+          clipper(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
               .backgroundClipRect(ClipRectsContext(
                   enclosingPaginationLayer(), clipRectsCacheSlot,
                   ExcludeOverlayScrollbarSizeForHitTesting))
@@ -2511,7 +2516,7 @@ LayoutRect PaintLayer::boundingBoxForCompositingInternal(
 
   // If there is a clip applied by an ancestor to this PaintLayer but below or
   // equal to |ancestorLayer|, apply that clip.
-  LayoutRect result = clipper().localClipRect(compositedLayer);
+  LayoutRect result = clipper(false).localClipRect(compositedLayer);
 
   result.intersect(physicalBoundingBox(LayoutPoint()));
 
@@ -2945,6 +2950,16 @@ void PaintLayer::styleDidChange(StyleDifference diff,
   layoutObject()->setNeedsPaintPropertyUpdate();
 }
 
+PaintLayerClipper PaintLayer::clipper(bool useGeometryMapper) const {

[pdr., 2017/02/10 20:51:07]

Can you add an enum for UseGeometryMapper to make the false/true's easier to
understand?

I worry we're failing to use the mapper in some cases and using it when we
shouldn't in others. Instead of passing this in at the callsites, could this
function pass a geometrymapper if the document lifecycle allows it, and not
otherwise? If there are cases when recursion should disallow it, maybe an
optional argument could be used for that?

IOW, something like:
PaintLayerClipper PaintLayer::clipper() const {
  GeometryMapper* geometryMapper = nullptr;
  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
    if (m_layoutObject->document()->lifecycle() >= InPrePaint)
      geometryMapper = ...
  }
  return PaintLayerClipper(*this, geometryMapper);
}

[chrishtr, 2017/02/10 22:56:36]

Done.
To date we do not have code which is conditional on lifecycle state, to my
knowledge. 
Instead we use it only for assertions.

+  GeometryMapper* geometryMapper = nullptr;
+  if (useGeometryMapper) {
+    DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
+    if (FrameView* frameView = m_layoutObject->document().view())
+      geometryMapper = frameView->geometryMapper();
+  }
+  return PaintLayerClipper(*this, geometryMapper);
+}
+
 bool PaintLayer::scrollsOverflow() const {
   if (PaintLayerScrollableArea* scrollableArea = this->getScrollableArea())
     return scrollableArea->scrollsOverflow();