SPv2: Paint SVG images and self-contained recorded pictures with their own trees.

third_party/WebKit/Source/platform/graphics/paint/ClipPaintPropertyNode.h

 // Copyright 2015 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.
 
 #ifndef ClipPaintPropertyNode_h
 #define ClipPaintPropertyNode_h
 
 #include "platform/PlatformExport.h"
 #include "platform/geometry/FloatRoundedRect.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 
 #include <iosfwd>
 
 namespace blink {
 
 // A clip rect created by a css property such as "overflow" or "clip".
 // Along with a reference to the transform space the clip rect is based on,
 // and a parent ClipPaintPropertyNode for inherited clips.
 //
 // The clip tree is rooted at a node with no parent. This root node should
 // not be modified.
 class PLATFORM_EXPORT ClipPaintPropertyNode
     : public RefCounted<ClipPaintPropertyNode> {
  public:
+  // This node is really a sentinel, and does not represent a real clip
+  // space.
   static ClipPaintPropertyNode* root();
 
   static PassRefPtr<ClipPaintPropertyNode> create(
       PassRefPtr<const ClipPaintPropertyNode> parent,
       PassRefPtr<const TransformPaintPropertyNode> localTransformSpace,
       const FloatRoundedRect& clipRect,
       CompositingReasons directCompositingReasons = CompositingReasonNone) {
     return adoptRef(new ClipPaintPropertyNode(
         std::move(parent), std::move(localTransformSpace), clipRect,
         directCompositingReasons));
@@ skipping 60 matching lines @@
   CompositingReasons m_directCompositingReasons;
 };
 
 // Redeclared here to avoid ODR issues.
 // See platform/testing/PaintPrinters.h.
 void PrintTo(const ClipPaintPropertyNode&, std::ostream*);
 
 }  // namespace blink
 
 #endif  // ClipPaintPropertyNode_h