Add support for analyzing individual URIs.

tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart

Index: tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
diff --git a/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart b/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
index 713281f61146bfa9749a451faaca1098baef693e..ac16a08a37cc9be56be14aaa0231577c8c8c786c 100644
--- a/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
+++ b/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
@@ -66,7 +66,8 @@ runTests(List<TestEntry> tests) {
   for (TestEntry test in tests) {
     Map files = {TEST_MAIN_FILE: test.source};
     asyncTest(() {
-      Compiler compiler = compilerFor(files, options: <String>['--use-cps-ir']);
+      Compiler compiler = compilerFor(
+          memorySourceFiles: files, options: <String>['--use-cps-ir']);
       ir.FunctionDefinition irNodeForMain;
 
       void cacheIrNodeForMain(Element function, ir.FunctionDefinition irNode) {