Only call finishLoad() if session actually loaded.

Source/modules/encryptedmedia/MediaKeySession.cpp

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 253 matching lines @@
     {
     }
 
     virtual ~LoadSessionResultPromise()
     {
     }
 
     // ContentDecryptionModuleResult implementation.
     virtual void completeWithSession(WebContentDecryptionModuleResult::SessionStatus status) override
     {
-        bool result = false;
         switch (status) {
         case WebContentDecryptionModuleResult::NewSession:
-            result = true;
-            break;
+            m_session->finishLoad();
+            resolve(true);
+            return;
 
         case WebContentDecryptionModuleResult::SessionNotFound:
-            result = false;
-            break;
+            resolve(false);
+            return;
 
         case WebContentDecryptionModuleResult::SessionAlreadyExists:
             ASSERT_NOT_REACHED();
             reject(InvalidStateError, "Unexpected completion.");
             return;
         }
 
-        m_session->finishLoad();
-        resolve(result);
+        ASSERT_NOT_REACHED();
     }
 
     DEFINE_INLINE_TRACE()
     {
         visitor->trace(m_session);
         ContentDecryptionModuleResultPromise::trace(visitor);
     }
 
 private:
     Member<MediaKeySession> m_session;
@@ skipping 622 matching lines @@
     visitor->trace(m_asyncEventQueue);
     visitor->trace(m_pendingActions);
     visitor->trace(m_mediaKeys);
     visitor->trace(m_keyStatusesMap);
     visitor->trace(m_closedPromise);
     RefCountedGarbageCollectedEventTargetWithInlineData<MediaKeySession>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink