Make Uri._makeQuery easier to analyze

sdk/lib/core/uri.dart

Index: sdk/lib/core/uri.dart
diff --git a/sdk/lib/core/uri.dart b/sdk/lib/core/uri.dart
index 51d66cfa8052a64fb1ad6235f4afee31e1c4a918..d7f911bfa55d98e782e3be82b6730191046c91b2 100644
--- a/sdk/lib/core/uri.dart
+++ b/sdk/lib/core/uri.dart
@@ -2066,11 +2066,13 @@ class _Uri implements Uri {
   static String _makeQuery(
       String query, int start, int end,
       Map<String, dynamic/*String|Iterable<String>*/> queryParameters) {
-    if (query == null && queryParameters == null) return null;
-    if (query != null && queryParameters != null) {
-      throw new ArgumentError('Both query and queryParameters specified');
+    if (query != null) {
+      if (queryParameters != null) {
+        throw new ArgumentError('Both query and queryParameters specified');
+      }
+      return _normalize(query, start, end, _queryCharTable);
     }
-    if (query != null) return _normalize(query, start, end, _queryCharTable);
+    if (queryParameters == null) return null;
 
     var result = new StringBuffer();
     var separator = "";