Change libraries map to use Uri.

tests/lib/mirrors/mirrors_test.dart

Index: tests/lib/mirrors/mirrors_test.dart
diff --git a/tests/lib/mirrors/mirrors_test.dart b/tests/lib/mirrors/mirrors_test.dart
index 3938fbb9360af546d26c170bab756fda03798785..fd7b0c8362acbfab5628357e62eafd60244044da 100644
--- a/tests/lib/mirrors/mirrors_test.dart
+++ b/tests/lib/mirrors/mirrors_test.dart
@@ -33,9 +33,13 @@ testInvoke(mirrors) {
 testFieldAccess(mirrors) {
   var instance = new Class();
 
-  var libMirror = mirrors.libraries[const Symbol("MirrorsTest")];
+  var libMirror = mirrors.findLibrary(const Symbol("MirrorsTest")).single;
   var classMirror = libMirror.classes[const Symbol("Class")];
   var instMirror = reflect(instance);
+  var fieldMirror = classMirror.members[new Symbol('field')];
+
+  expect(fieldMirror is VariableMirror, isTrue);
+  expect(fieldMirror.type, equals(mirrors.dynamicType));
 
   libMirror.setField(const Symbol('topLevelField'), [91]);
   expect(libMirror.getField(const Symbol('topLevelField')).reflectee,
@@ -83,7 +87,7 @@ testClosureMirrors(mirrors) {
 }
 
 testInvokeConstructor(mirrors) {
-  var libMirror = mirrors.libraries[const Symbol("MirrorsTest")];
+  var libMirror = mirrors.findLibrary(const Symbol("MirrorsTest")).single;
   var classMirror = libMirror.classes[const Symbol("Class")];
 
   var instanceMirror = classMirror.newInstance(const Symbol(''),[]);
@@ -122,7 +126,7 @@ testReflectClass(mirrors) {
 }
 
 testNames(mirrors) {
-  var libMirror = mirrors.libraries[const Symbol('MirrorsTest')];
+  var libMirror = mirrors.findLibrary(const Symbol("MirrorsTest")).single;
   var classMirror = libMirror.classes[const Symbol('Class')];
   var typedefMirror = libMirror.members[const Symbol('Typedef')];
   var methodMirror = libMirror.functions[const Symbol('testNames')];