Oilpan: have PendingScripts trace their script elements.

Source/core/dom/ScriptRunner.h

Index: Source/core/dom/ScriptRunner.h
diff --git a/Source/core/dom/ScriptRunner.h b/Source/core/dom/ScriptRunner.h
index b47139c86298105a835a442ce1ac0e1d07cc64aa..1f9a4703b09638d8a19bd7a144b332d26ceb1951 100644
--- a/Source/core/dom/ScriptRunner.h
+++ b/Source/core/dom/ScriptRunner.h
@@ -39,6 +39,7 @@ class ScriptResource;
 class Document;
 class PendingScript;
 class ScriptLoader;
+class Visitor;
 
 class ScriptRunner {

[Mads Ager (chromium), 2014/05/26 13:55:36]

I think we could move ScriptRunner to the oilpan heap without issues.
ScriptRunner is owned by the Document and as far as I can tell it is only ever
destructed when the document is going away as well. The only thing it does is
decrement delay-the-load event counts in the document. However, if the document
is going away that shouldn't be necessary (we will not dispatch a load event
when the document is dead anyway)? If that reasoning is correct we should be
able to move this to the heap and have traced Members in both directions and not
update any counts in the destructor here.

[sof, 2014/05/27 08:31:04]

Yes, moving ScriptRunner is doable and easier than its parser counter part
HTMLScriptRunner.

Decrementing those Document counts doesn't seem like a productive operation
Oilpan or not; I emptied the destructor.

     WTF_MAKE_NONCOPYABLE(ScriptRunner); WTF_MAKE_FAST_ALLOCATED;
@@ -54,6 +55,8 @@ public:
     void notifyScriptReady(ScriptLoader*, ExecutionType);
     void notifyScriptLoadError(ScriptLoader*, ExecutionType);
 
+    void trace(Visitor*);
+
 private:
     explicit ScriptRunner(Document*);