Oilpan: tidy up some inter-stack object references.

Source/core/css/parser/CSSParserObserverWrapper.h

Index: Source/core/css/parser/CSSParserObserverWrapper.h
diff --git a/Source/core/css/parser/CSSParserObserverWrapper.h b/Source/core/css/parser/CSSParserObserverWrapper.h
index 1aff9fcdb42e4478047de7b545a31f211f87cbcd..105a844652cd90374c469c075aaedffa4f30c49c 100644
--- a/Source/core/css/parser/CSSParserObserverWrapper.h
+++ b/Source/core/css/parser/CSSParserObserverWrapper.h
@@ -11,8 +11,8 @@ namespace blink {
 
 class CSSParserObserverWrapper {
 public:
-    CSSParserObserverWrapper(CSSParserObserver& observer)
-    : m_observer(observer)
+    explicit CSSParserObserverWrapper(CSSParserObserver& observer)
+        : m_observer(observer)
     { }
 
     unsigned startOffset(const CSSParserTokenRange&);
@@ -36,6 +36,9 @@ public:
     }
 
 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;