[SPv2] Use PassRefPtr in PropertyTreeState setter and remove meaningless DCHECK

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

 // 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.
 
 #ifndef PropertyTreeState_h
 #define PropertyTreeState_h
 
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/EffectPaintPropertyNode.h"
 #include "platform/graphics/paint/ScrollPaintPropertyNode.h"
@@ skipping 20 matching lines @@
     DCHECK(!m_transform || !m_transform->hasOneRef());
     DCHECK(!m_clip || !m_clip->hasOneRef());
     DCHECK(!m_effect || !m_effect->hasOneRef());
     DCHECK(!m_scroll || !m_scroll->hasOneRef());
   }
 
   const TransformPaintPropertyNode* transform() const {
     DCHECK(!m_transform || !m_transform->hasOneRef());
     return m_transform.get();
   }
-  void setTransform(const TransformPaintPropertyNode* node) {
+  void setTransform(PassRefPtr<const TransformPaintPropertyNode> node) {
     m_transform = node;
-    DCHECK(!node->hasOneRef());

[trchen, 2016/12/15 04:15:52]

Just realized this DCHECK makes no sense. The only way 'node' could have exactly
1 reference at this point is that m_transform.get() == node in the beginning.
Otherwise assigning to m_transform increases reference count by 1, and the
reference count should already be 1 or more in the beginning.

   }
 
   const ClipPaintPropertyNode* clip() const {
     DCHECK(!m_clip || !m_clip->hasOneRef());
     return m_clip.get();
   }
-  void setClip(const ClipPaintPropertyNode* node) {
-    m_clip = node;
-    DCHECK(!node->hasOneRef());
-  }
+  void setClip(PassRefPtr<const ClipPaintPropertyNode> node) { m_clip = node; }
 
   const EffectPaintPropertyNode* effect() const {
     DCHECK(!m_effect || !m_effect->hasOneRef());
     return m_effect.get();
   }
-  void setEffect(const EffectPaintPropertyNode* node) {
+  void setEffect(PassRefPtr<const EffectPaintPropertyNode> node) {
     m_effect = node;
-    DCHECK(!node->hasOneRef());
   }
 
   const ScrollPaintPropertyNode* scroll() const {
     DCHECK(!m_scroll || !m_scroll->hasOneRef());
     return m_scroll.get();
   }
-  void setScroll(const ScrollPaintPropertyNode* node) {
+  void setScroll(PassRefPtr<const ScrollPaintPropertyNode> node) {
     m_scroll = node;
-    DCHECK(!node->hasOneRef());
   }
 
  private:
   RefPtr<const TransformPaintPropertyNode> m_transform;
   RefPtr<const ClipPaintPropertyNode> m_clip;
   RefPtr<const EffectPaintPropertyNode> m_effect;
   RefPtr<const ScrollPaintPropertyNode> m_scroll;
 };
 
 inline bool operator==(const PropertyTreeState& a, const PropertyTreeState& b) {
   return a.transform() == b.transform() && a.clip() == b.clip() &&
          a.effect() == b.effect() && a.scroll() == b.scroll();
 }
 
 }  // namespace blink
 
 #endif  // PropertyTreeState_h