Revert of Fix issue of localDescription and remoteDescription getter.

Source/modules/mediastream/RTCPeerConnection.idl

Index: Source/modules/mediastream/RTCPeerConnection.idl
diff --git a/Source/modules/mediastream/RTCPeerConnection.idl b/Source/modules/mediastream/RTCPeerConnection.idl
index f0e5a07a5727027a208ee989685b24dc08168c1f..fa5494606e720f8f19b2043bc0492e96f623dd77 100644
--- a/Source/modules/mediastream/RTCPeerConnection.idl
+++ b/Source/modules/mediastream/RTCPeerConnection.idl
@@ -35,18 +35,16 @@
     ConstructorCallWith=ExecutionContext,
     NoInterfaceObject,
     RaisesException=Constructor,
-    SetWrapperReferenceTo(RTCSessionDescription localDescription,
-                          RTCSessionDescription remoteDescription)
 ] interface RTCPeerConnection : EventTarget {
     [RaisesException] void createOffer(RTCSessionDescriptionCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary rtcOfferOptions);
 
     [RaisesException] void createAnswer(RTCSessionDescriptionCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback, optional Dictionary mediaConstraints);
 
     [RaisesException] void setLocalDescription(RTCSessionDescription description, [Default=Undefined] optional VoidCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback);
-    readonly attribute RTCSessionDescription localDescription;
+    [RaisesException=Getter] readonly attribute RTCSessionDescription localDescription;
 
     [RaisesException] void setRemoteDescription(RTCSessionDescription description, [Default=Undefined] optional VoidCallback successCallback, [Default=Undefined] optional RTCErrorCallback failureCallback);
-    readonly attribute RTCSessionDescription remoteDescription;
+    [RaisesException=Getter] readonly attribute RTCSessionDescription remoteDescription;
 
     readonly attribute DOMString signalingState;