Add packageUriResolver before ResourceUriResolver.

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 5347e14c97a5ee2771e9a6c4a20f00b154a8550c..f5430ac3b9bd476c9657825d52d4f0c279dc5d11 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -1233,12 +1233,11 @@ class ServerContextManager extends ContextManager {
    * [packageUriResolver].
    */
   SourceFactory _createSourceFactory(UriResolver packageUriResolver) {
-    List<UriResolver> resolvers = <UriResolver>[
-        new DartUriResolver(analysisServer.defaultSdk),
-        new ResourceUriResolver(resourceProvider)];
-    if (packageUriResolver != null) {
-      resolvers.add(packageUriResolver);
-    }
+    UriResolver dartResolver = new DartUriResolver(analysisServer.defaultSdk);
+    UriResolver resourceResolver = new ResourceUriResolver(resourceProvider);
+    List<UriResolver> resolvers = packageUriResolver != null ?
+        <UriResolver>[dartResolver, packageUriResolver, resourceResolver] :
+        <UriResolver>[dartResolver, resourceResolver];
     return new SourceFactory(resolvers);
   }
 }