Apply SVG viewport clips in PaintLayer; paint background of replaced like boxes.

third_party/WebKit/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 "core/paint/BoxClipper.h"
 
 #include "core/layout/LayoutBox.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintInfo.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/ClipDisplayItem.h"
 #include "platform/graphics/paint/PaintController.h"
 
 namespace blink {
 
+// Clips for boxes are applied by the box's PaintLayerClipper, if the box has
+// a self-painting PaintLayer. Otherwise the box clips itself.
+// Note that this method is very similar to
+// PaintLayerClipper::shouldClipOverflow for that reason.
+//
+// An exception is control clip, which is currently never applied by
+// PaintLayerClipper.
 static bool boxNeedsClip(const LayoutBox& box) {
   if (box.hasControlClip())
     return true;
+  if (box.hasLayer() && box.layer()->isSelfPaintingLayer())
+    return false;
   if (box.isSVGRoot() && toLayoutSVGRoot(box).shouldApplyViewportClip())
     return true;
-  if (box.hasLayer() && box.layer()->isSelfPaintingLayer())
-    return false;
   return box.hasOverflowClip() || box.styleRef().containsPaint();
 }
 
 DISABLE_CFI_PERF
 BoxClipper::BoxClipper(const LayoutBox& box,
                        const PaintInfo& paintInfo,
                        const LayoutPoint& accumulatedOffset,
                        ContentsClipBehavior contentsClipBehavior)
     : m_box(box),
       m_paintInfo(paintInfo),
@@ skipping 62 matching lines @@
 BoxClipper::~BoxClipper() {
   if (m_clipType == DisplayItem::kUninitializedType)
     return;
 
   DCHECK(boxNeedsClip(m_box));
   m_paintInfo.context.getPaintController().endItem<EndClipDisplayItem>(
       m_box, DisplayItem::clipTypeToEndClipType(m_clipType));
 }
 
 }  // namespace blink