Oilpan: tidy up some inter-stack object references.

Source/core/css/parser/CSSParserObserverWrapper.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 CSSParserObserverWrapper_h
 #define CSSParserObserverWrapper_h
 
 #include "core/css/parser/CSSParserObserver.h"
 
 namespace blink {
 
 class CSSParserObserverWrapper {
 public:
-    CSSParserObserverWrapper(CSSParserObserver& observer)
-    : m_observer(observer)
+    explicit CSSParserObserverWrapper(CSSParserObserver& observer)
+        : m_observer(observer)
     { }
 
     unsigned startOffset(const CSSParserTokenRange&);
     unsigned previousTokenStartOffset(const CSSParserTokenRange&);
     unsigned endOffset(const CSSParserTokenRange&); // Includes trailing comments
 
     void skipCommentsBefore(const CSSParserTokenRange&, bool leaveDirectlyBefore);
     void yieldCommentsBefore(const CSSParserTokenRange&);
 
     CSSParserObserver& observer() { return m_observer; }
     void addComment(unsigned startOffset, unsigned endOffset, unsigned tokensBefore)
     {
         CommentPosition position = {startOffset, endOffset, tokensBefore};
         m_commentOffsets.append(position);
     }
     void addToken(unsigned startOffset) { m_tokenOffsets.append(startOffset); }
     void finalizeConstruction(CSSParserToken* firstParserToken)
     {
         m_firstParserToken = firstParserToken;
         m_commentIterator = m_commentOffsets.begin();
     }
 
 private:
+    // Oilpan: CSSParserObserver is stack allocated and stack scanning will
+    // separately locate it.
+    GC_PLUGIN_IGNORE("509911")
     CSSParserObserver& m_observer;

[haraken, 2015/08/07 08:17:56]

Shall we change this to a RawPtrWillBeMember? (I think we have done it in many
places.)

[sof, 2015/08/07 08:20:20]

We can't - it's currently marked as STACK_ALLOCATED().

[haraken, 2015/08/07 08:27:38]

ah, understand. Maybe it would make more sense to update the plugin so that it
doesn't detect this as a problematic pointer.

[sof, 2015/08/07 09:11:07]

Stack references held by stack "hosts" are recognized and supported by the GC
plugin.

This "wrapper" type is indeed always stack allocated, so just annotating it with
STACK_ALLOCATED() is sufficient here. IOW, we can do better :) Updated the CL.

     Vector<unsigned> m_tokenOffsets;
     CSSParserToken* m_firstParserToken;
 
     struct CommentPosition {
         unsigned startOffset;
         unsigned endOffset;
         unsigned tokensBefore;
     };
 
     Vector<CommentPosition> m_commentOffsets;
     Vector<CommentPosition>::iterator m_commentIterator;
 };
 
 } // namespace blink
 
 #endif // CSSParserObserverWrapper_h