[Fetch API] Put body members directly on Response/Request

Source/modules/serviceworkers/Request.idl

Index: Source/modules/serviceworkers/Request.idl
diff --git a/Source/modules/serviceworkers/Request.idl b/Source/modules/serviceworkers/Request.idl
index 11a56d306b1e29bbc57fb4e319d955137e919a1a..a5bf88129c10542ec1a18d23d2580b574af10393 100644
--- a/Source/modules/serviceworkers/Request.idl
+++ b/Source/modules/serviceworkers/Request.idl
@@ -19,7 +19,6 @@ enum RequestCredentials { "omit", "same-origin", "include" };
     readonly attribute ByteString method;
     readonly attribute ScalarValueString url;
     readonly attribute Headers headers;
-    [CallWith=ExecutionContext] readonly attribute FetchBodyStream body;
 
     readonly attribute DOMString referrer;
     readonly attribute RequestMode mode;
@@ -28,3 +27,5 @@ enum RequestCredentials { "omit", "same-origin", "include" };
     // FIXME: Implement the following:
     // readonly attribute RequestContext context;
 };
+
+Request implements Body;