Oilpan: Ensure that classes with virtual trace methods always have vtables for their left-most base…

Source/core/fetch/ResourceClient.h

Index: Source/core/fetch/ResourceClient.h
diff --git a/Source/core/fetch/ResourceClient.h b/Source/core/fetch/ResourceClient.h
index 16112d2cbd411e272f9f54324013cef2289a691f..28b1738c3249824750a8df8120c836f8d483a76f 100644
--- a/Source/core/fetch/ResourceClient.h
+++ b/Source/core/fetch/ResourceClient.h
@@ -25,6 +25,7 @@
 #ifndef ResourceClient_h
 #define ResourceClient_h
 
+#include "platform/heap/Handle.h"

[Mads Ager (chromium), 2014/08/12 06:07:04]

You should be able to just forward declare Visitor (in the same way it is done
for Resource) instead of including Handle.h here.

[haraken, 2014/08/12 06:15:50]

I don't have a strong opinion here, but I guess that the current rule would be
just "include Handle.h so that the code compiles". Given that Handle.h has no
risk of creating include cycles, the rule will just work. (We're following the
rule for v8.h.)

 #include "wtf/FastAllocBase.h"
 #include "wtf/Forward.h"
 
@@ -48,6 +49,8 @@ public:
     static ResourceClientType expectedType() { return BaseResourceType; }
     virtual ResourceClientType resourceClientType() const { return expectedType(); }
 
+    virtual void trace(Visitor*) { }
+
 protected:
     ResourceClient() { }
 };