define trait type explicitly

Author: tsuyoshizawa

play2-oauth2-provider/src/main/scala/scalaoauth2/provider/OAuth2Provider.scala

@@ -13,9 +13,9 @@ import scala.concurrent.duration._
  */
 trait OAuth2BaseProvider extends Results {
 
-  val protectedResource = ProtectedResource
+  val protectedResource: ProtectedResource = ProtectedResource
 
-  val tokenEndpoint = TokenEndpoint
+  val tokenEndpoint: TokenEndpoint = TokenEndpoint
 
   implicit def play2oauthRequest(request: RequestHeader): AuthorizationRequest = {
     AuthorizationRequest(request.headers.toMap, request.queryString)