Add toString() for paint property node classes

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

 // Copyright 2016 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 "platform/graphics/paint/ClipPaintPropertyNode.h"
 
 #include "platform/geometry/LayoutRect.h"
 
 namespace blink {
 
 ClipPaintPropertyNode* ClipPaintPropertyNode::root() {
   DEFINE_STATIC_REF(ClipPaintPropertyNode, root,
                     (ClipPaintPropertyNode::create(
                         nullptr, TransformPaintPropertyNode::root(),
                         FloatRoundedRect(LayoutRect::infiniteIntRect()))));
   return root;
 }
 
+String ClipPaintPropertyNode::toString() const {
+  return String::format("localTransformSpace=%p rect=%s",
+                        m_localTransformSpace.get(),
+                        m_clipRect.toString().ascii().data());
+}
+
 }  // namespace blink