Introduce infrastructure for tracing ScriptWrappables.

third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h

Index: third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h b/third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h
index 62484cd14861a310549c7111a919b2e2a084a0b8..eee3802cfd843abfec60f9a3a73c574cc146d732 100644
--- a/third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h
+++ b/third_party/WebKit/Source/bindings/core/v8/DOMDataStore.h
@@ -153,6 +153,14 @@ public:
         return m_wrapperMap->newLocal(isolate, object);
     }
 
+    void markWrapper(ScriptWrappable* scriptWrappable, v8::Isolate* isolate)
+    {
+        if (m_isMainWorld)
+            scriptWrappable->markWrapper(isolate);

[haraken, 2016/04/18 04:35:41]

Sorry, this would be a bug of the existing bindings... You'll never this branch
because all wrappers in the main world are stored in ScriptWrappables (i.e.,
doesn't use DOMDataStore at all).

If you ever hit this branch, I guess you'll run into an infinite tracing loop.

(I'll remove the m_isMainWorld and make sure that DOMDataStore is used only by
isolated worlds.)

[Marcel Hlopko, 2016/04/18 11:45:34]

Yeah, I see. Good catch. I fixed the code.

+        else
+            m_wrapperMap->markWrapper(scriptWrappable);
+    }
+
     void setReference(const v8::Persistent<v8::Object>& parent, ScriptWrappable* child, v8::Isolate* isolate)
     {
         if (m_isMainWorld) {