Eagerly sweep MediaKeySession objects.

Source/modules/encryptedmedia/NavigatorRequestMediaKeySystemAccess.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NavigatorRequestMediaKeySystemAccess_h
 #define NavigatorRequestMediaKeySystemAccess_h
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/modules/v8/V8MediaKeySystemConfiguration.h"
 #include "core/frame/Navigator.h"
 #include "modules/encryptedmedia/MediaKeySystemConfiguration.h"
-#include "wtf/Vector.h"
-#include "wtf/text/WTFString.h"
+#include "platform/heap/Handle.h"
+#include "wtf/Forward.h"
 
 namespace blink {
 
 class NavigatorRequestMediaKeySystemAccess {
 public:
     static ScriptPromise requestMediaKeySystemAccess(
         ScriptState*,
         Navigator&,
         const String& keySystem,
         const HeapVector<MediaKeySystemConfiguration>& supportedConfigurations);
 
 private:
     NavigatorRequestMediaKeySystemAccess();
 };
 
 } // namespace blink
 
 #endif // NavigatorRequestMediaKeySystemAccess_h