NOT FOR LANDING Introduce and use WebMediaSession

Source/bindings/core/v8/CallbackPromiseAdapter.h

Index: Source/bindings/core/v8/CallbackPromiseAdapter.h
diff --git a/Source/bindings/core/v8/CallbackPromiseAdapter.h b/Source/bindings/core/v8/CallbackPromiseAdapter.h
index 04f69dc90ae11fa549d599ca3d41f9e2fb6e1050..9dd469d9297ae312f38d15c46babf65ae7f0f322 100644
--- a/Source/bindings/core/v8/CallbackPromiseAdapter.h
+++ b/Source/bindings/core/v8/CallbackPromiseAdapter.h
@@ -185,6 +185,7 @@ private:
         {
             typename T::WebType result(adopt(e));
             ScriptPromiseResolver* resolver = this->resolver();
+            ScriptState::Scope scope(resolver->scriptState());
             if (!resolver->executionContext() || resolver->executionContext()->activeDOMObjectsAreStopped())
                 return;
             resolver->reject(T::take(resolver, pass(result)));