Invalidate subsequence caching & empty paint phases if clips changed.

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

Index: third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
index b8b71d4fb8e797175369a82539f15252e8294057..fa65bb692d88b92e87a6e22d4c8ee1ce08e778dc 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipper.cpp
@@ -160,8 +160,8 @@ ClipRects& PaintLayerClipper::storeClipRectsInCache(
 
 ClipRects& PaintLayerClipper::getClipRects(
     const ClipRectsContext& context) const {
-  if (ClipRects* result = clipRectsIfCached(context))
-    return *result;
+  // if (ClipRects* result = clipRectsIfCached(context))
+  //   return *result;
   // Note that it's important that we call getClipRects on our parent
   // before we call calculateClipRects so that calculateClipRects will hit
   // the cache.
@@ -169,6 +169,8 @@ ClipRects& PaintLayerClipper::getClipRects(
   if (context.rootLayer != &m_layer && m_layer.parent())
     parentClipRects = &m_layer.parent()->clipper().getClipRects(context);
   RefPtr<ClipRects> clipRects = ClipRects::create();
+  //  LOG(ERROR) << "calculateClipRects:" <<
+  //  m_layer.layoutObject()->debugName();
   calculateClipRects(context, *clipRects);
   return storeClipRectsInCache(context, parentClipRects, *clipRects);
 }
@@ -389,6 +391,7 @@ void PaintLayerClipper::calculateClipRects(const ClipRectsContext& context,
   if (!m_layer.parent() &&
       !RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
     // The root layer's clip rect is always infinite.
+    // LOG(ERROR) << "wat";
     clipRects.reset(LayoutRect(LayoutRect::infiniteIntRect()));
     return;
   }
@@ -408,16 +411,19 @@ void PaintLayerClipper::calculateClipRects(const ClipRectsContext& context,
   }
 
   adjustClipRectsForChildren(layoutObject, clipRects);
-
+  // LOG(ERROR) << "just before: " << m_layer.layoutObject()->debugName();
   if (shouldClipOverflow(context) || layoutObject.hasClip()) {
+    //  LOG(ERROR) << "clipping overflow: " <<
+    //  m_layer.layoutObject()->debugName();
     // This offset cannot use convertToLayerCoords, because sometimes our
     // rootLayer may be across some transformed layer boundary, for example, in
     // the PaintLayerCompositor overlapMap, where clipRects are needed in view
     // space.
-    applyClipRects(context, layoutObject,
-                   LayoutPoint(layoutObject.localToAncestorPoint(
-                       FloatPoint(), context.rootLayer->layoutObject())),
-                   clipRects);
+    LOG(ERROR) << "mapping to ancestor: from=" << layoutObject.debugName()
+               << " to=" << context.rootLayer->layoutObject()->debugName();
+    LayoutPoint point(layoutObject.localToAncestorPoint(
+        FloatPoint(), context.rootLayer->layoutObject()));
+    applyClipRects(context, layoutObject, point, clipRects);
   }
 }
 
@@ -479,6 +485,7 @@ ClipRect PaintLayerClipper::applyOverflowClipToBackgroundRectWithGeometryMapper(
     const ClipRect& clip) const {
   const LayoutObject& layoutObject = *m_layer.layoutObject();
   FloatRect clipRect(clip.rect());
+  // fix??
   if (shouldClipOverflow(context)) {
     LayoutRect layerBoundsWithVisualOverflow =
         layoutObject.isLayoutView()
@@ -543,11 +550,11 @@ bool PaintLayerClipper::shouldClipOverflow(
     const ClipRectsContext& context) const {
   if (!m_layer.layoutObject()->isBox())
     return false;
+  // LOG(ERROR) << "wat";
   const LayoutBox& box = *toLayoutBox(m_layer.layoutObject());
 
   if (!shouldRespectOverflowClip(context))
     return false;
-
   return box.shouldClipOverflow();
 }