Generate scroll/clip display item hierarchy for SPv2

Source/core/paint/BoxClipper.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/BoxClipper.h"
 
 #include "core/layout/LayoutBox.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "core/paint/PaintInfo.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/ClipDisplayItem.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 
 namespace blink {
 
 BoxClipper::BoxClipper(const LayoutBox& box, const PaintInfo& paintInfo, const LayoutPoint& accumulatedOffset, ContentsClipBehavior contentsClipBehavior)
     : m_box(box)
     , m_paintInfo(paintInfo)
     , m_clipType(DisplayItem::UninitializedType)
 {
     if (m_paintInfo.phase == PaintPhaseBlockBackground || m_paintInfo.phase == PaintPhaseSelfOutline || m_paintInfo.phase == PaintPhaseMask)
         return;
 
     bool isControlClip = m_box.hasControlClip();
-    bool isOverflowClip = m_box.hasOverflowClip() && !m_box.layer()->isSelfPaintingLayer();
+    bool isOverflowClip = m_box.hasOverflowClip() && (!m_box.layer()->isSelfPaintingLayer() || RuntimeEnabledFeatures::slimmingPaintV2Enabled());

[pdr., 2015/09/03 06:16:59]

Should we return false from isSelfPaintingLayer when spv2 is on?

[trchen, 2015/09/04 06:10:14]

Nope it affects painting order. Most of the time isSelfPaintingLayer means being
a (pseudo) stacking context.

 
     if (!isControlClip && !isOverflowClip)
         return;
 
     LayoutRect clipRect = isControlClip ? m_box.controlClipRect(accumulatedOffset) : m_box.overflowClipRect(accumulatedOffset);
     FloatRoundedRect clipRoundedRect(0, 0, 0, 0);
     bool hasBorderRadius = m_box.style()->hasBorderRadius();
     if (hasBorderRadius)
         clipRoundedRect = m_box.style()->getRoundedInnerBorderFor(LayoutRect(accumulatedOffset, m_box.size()));
 
-    if (contentsClipBehavior == SkipContentsClipIfPossible) {
+    if (contentsClipBehavior == SkipContentsClipIfPossible && !RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
         LayoutRect contentsVisualOverflow = m_box.contentsVisualOverflowRect();
         if (contentsVisualOverflow.isEmpty())
             return;
 
         LayoutRect conservativeClipRect = clipRect;
         if (hasBorderRadius)
             conservativeClipRect.intersect(LayoutRect(clipRoundedRect.radiusCenterRect()));
         conservativeClipRect.moveBy(-accumulatedOffset);
         if (m_box.hasLayer())
             conservativeClipRect.move(m_box.scrolledContentOffset());
@@ skipping 18 matching lines @@
         ClipDisplayItem clipDisplayItem(m_box, m_clipType, pixelSnappedIntRect(clipRect), roundedRects);
         clipDisplayItem.replay(*paintInfo.context);
     }
 }
 
 BoxClipper::~BoxClipper()
 {
     if (m_clipType == DisplayItem::UninitializedType)
         return;
 
-    ASSERT(m_box.hasControlClip() || (m_box.hasOverflowClip() && !m_box.layer()->isSelfPaintingLayer()));
+    ASSERT(m_box.hasControlClip() || (m_box.hasOverflowClip() && (!m_box.layer()->isSelfPaintingLayer() || RuntimeEnabledFeatures::slimmingPaintV2Enabled())));
 
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(m_paintInfo.context->displayItemList());
         if (!m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled()) {
             if (m_paintInfo.context->displayItemList()->lastDisplayItemIsNoopBegin())
                 m_paintInfo.context->displayItemList()->removeLastDisplayItem();
             else
                 m_paintInfo.context->displayItemList()->createAndAppend<EndClipDisplayItem>(m_box, DisplayItem::clipTypeToEndClipType(m_clipType));
         }
     } else {
         EndClipDisplayItem endClipDisplayItem(m_box, DisplayItem::clipTypeToEndClipType(m_clipType));
         endClipDisplayItem.replay(*m_paintInfo.context);
     }
 }
 
 } // namespace blink