Make ScriptPromiseResolver RefCountedWillBeRefCountedGarbageCollected.

LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html

Index: LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html b/LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html
index 39d16057376bb8f8826fa5366e9098374fa804e8..44da7116509e88442807da3ea150166db31959ac 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-lifetime-mediakeysession-release.html
@@ -36,19 +36,27 @@
                     mediaKeys = result;
 
                     // Verify MediaKeys are not an ActiveDOMObject.
-                    assert_equals(numActiveDOMObjectsCreated(), 0, 'MediaKeys.create()');
+                    // MediaKeys are not an ActiveDOMObject, but when creating MediaKeys,
+                    // creating ScriptPromiseResolvers, which are ActiveDOMObjects.
+                    // so numActiveDOMObjetsCreated() <= 2 (1 is MediaKeysInitializer and
+                    // the other is MediaKeySystemAccessInitializer).
+                    // When enabling oilpan, the ScriptPromiseResolvers are not destroyed
+                    // immediately. So numActiveDOMObjectsCreate() <= 2.
+                    assert_less_than_equal(numActiveDOMObjectsCreated(), 2, 'MediaKeys.create()');
 
                     mediaKeySession1 = mediaKeys.createSession();
                     return mediaKeySession1.generateRequest(initDataType, initData);
                 }).then(function() {
                     // Should be 1 MediaKeySession.
-                    assert_equals(numActiveDOMObjectsCreated(), 1, 'mediaKeys.createSession(1)');
+                    // numActiveDOMObjectsCreated() <= 4 (1 is a ScriptPromiseResolver owned by
+                    // ContentDecryptionModuleResultPromise and the other is MediaKeySession).
+                    assert_less_than_equal(numActiveDOMObjectsCreated(), 4, 'MediaKeys.createSession(1)');
                     mediaKeySession2 = mediaKeys.createSession();
                     return mediaKeySession2.generateRequest(initDataType, initData);
                 }).then(function() {
                     // Should be 2 MediaKeySessions.
-                    assert_equals(numActiveDOMObjectsCreated(), 2, 'mediaKeys.createSession(2)');
-
+                    // numActiveDOMObjectsCreated() <= 6 (ditto)
+                    assert_less_than_equal(numActiveDOMObjectsCreated(), 6, 'mediaKeys.createSession(2)');
                     // Close the sessions. Once completed, only the JS
                     // reference to them keeps them around.
                     return mediaKeySession1.close();
@@ -59,7 +67,13 @@
                     // reference to them from JS will result in the session
                     // being garbage-collected.
                     // Should be 2 MediaKeySessions.
-                    assert_equals(numActiveDOMObjectsCreated(), 2);
+
+                    // MediaKeySession::close uses ContentDecryptionModuleResultPromise.
+                    // ContentDecryptionModuleResultPromise owns 1 ScriptPromiseResolver, an
+                    // ActiveDOMObject. When enabling oilpan,
+                    // the ContentDecryptionModuleResultPromise might have not been collected yet.
+                    // So numActiveDOMObjectsCreated() <= 8.
+                    assert_less_than_equal(numActiveDOMObjectsCreated(), 8, 'after close');
 
                     mediaKeySession1 = null;
                     return createGCPromise();