Introduce infrastructure for tracing ScriptWrappables.

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

Index: third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h b/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h
index aab62ffe582846471e05607dd8a09c861cb5d8c3..d5804194b83f5cf8f4401829bd718b70c97d6264 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h
@@ -11,6 +11,7 @@
 namespace blink {
 
 class ScriptWrappable;
+class ScriptWrappableVisitor;
 
 /**
  * Classes deriving from ActiveScriptWrappable will be registered in a
@@ -22,6 +23,8 @@ class CORE_EXPORT ActiveScriptWrappable {
 public:
     explicit ActiveScriptWrappable(ScriptWrappable*);
 
+    static void traceActiveScriptWrappables(ScriptWrappableVisitor*);

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

traceActiveScriptWrappables => traceWrappers (for consistency)

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

Cannot, sadly. C++ is confused. ActiveScriptWrappables are also
ScriptWrappables, so there are then 2 methods called traceWrappers, one
instance, one static, and that's ambiguous.

+
     virtual bool hasPendingActivity() const = 0;
 
     ScriptWrappable* toScriptWrappable() const;