Fix issue of localDescription and remoteDescription getter.

Source/modules/mediastream/RTCSessionDescription.h

 /*
  * Copyright (C) 2012 Google 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
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef RTCSessionDescription_h
 #define RTCSessionDescription_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
+#include "core/dom/ActiveDOMObject.h"
 #include "public/platform/WebRTCSessionDescription.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class RTCSessionDescriptionInit;
 class ScriptState;
 class ScriptValue;
 
-class RTCSessionDescription final : public GarbageCollectedFinalized<RTCSessionDescription>, public ScriptWrappable {
+class RTCSessionDescription final
+    : public GarbageCollectedFinalized<RTCSessionDescription>
+    , public ScriptWrappable
+    , public ActiveDOMObject {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static RTCSessionDescription* create(const RTCSessionDescriptionInit&);
-    static RTCSessionDescription* create(WebRTCSessionDescription);
+    static RTCSessionDescription* create(ExecutionContext*, const RTCSessionDescriptionInit&);
+    static RTCSessionDescription* create(ExecutionContext*, WebRTCSessionDescription);
 
     String type();
     void setType(const String&);
 
     String sdp();
     void setSdp(const String&);
 
     ScriptValue toJSONForBinding(ScriptState*);
 
     WebRTCSessionDescription webSessionDescription();
+    void setWebSessionDescription(WebRTCSessionDescription);
 
-    DEFINE_INLINE_TRACE() { }
+    // ActiveDOMObject
+    bool hasPendingActivity() const override;
+    void stop() override;
+
+    DECLARE_VIRTUAL_TRACE();
 
 private:
-    explicit RTCSessionDescription(WebRTCSessionDescription);
+    RTCSessionDescription(ExecutionContext*, WebRTCSessionDescription);
 
     WebRTCSessionDescription m_webSessionDescription;
 };
 
 } // namespace blink
 
 #endif // RTCSessionDescription_h