Recompute librariesByName after loading a deferred library.

sdk/lib/_internal/compiler/js_lib/js_mirrors.dart

Index: sdk/lib/_internal/compiler/js_lib/js_mirrors.dart
diff --git a/sdk/lib/_internal/compiler/js_lib/js_mirrors.dart b/sdk/lib/_internal/compiler/js_lib/js_mirrors.dart
index 3ff978985ee12103d4ce7d14321962885c4c89b2..a17fc1ea5fb9b92a96c2e6449c87799feb33162e 100644
--- a/sdk/lib/_internal/compiler/js_lib/js_mirrors.dart
+++ b/sdk/lib/_internal/compiler/js_lib/js_mirrors.dart
@@ -48,7 +48,8 @@ import 'dart:_js_helper' show
     runtimeTypeToString,
     setRuntimeTypeInfo,
     throwInvalidReflectionError,
-    TypeImpl;
+    TypeImpl,
+    librariesUpdatedHook;
 
 import 'dart:_interceptors' show
     Interceptor,
@@ -97,8 +98,15 @@ class JsMirrorSystem implements MirrorSystem {
       new JsTypeMirror(const Symbol('dynamic'));
   static final JsTypeMirror _voidType = new JsTypeMirror(const Symbol('void'));
 
-  static final Map<String, List<LibraryMirror>> librariesByName =
-      computeLibrariesByName();
+  static Map<String, List<LibraryMirror>> _librariesByName;
+
+  static Map<String, List<LibraryMirror>> get librariesByName {
+    if (_librariesByName == null) {
+      _librariesByName = computeLibrariesByName();
+      librariesUpdatedHook = () => _librariesByName = computeLibrariesByName();

[floitsch, 2014/09/11 09:01:27]

() => _librariesByName = null.

When there are several files that are loaded we don't want to compute the
libraries one by one.
You will want to make the deferredLoad registration depending (on a local
boolean flag?)

[sigurdm, 2014/09/11 12:06:44]

Done.

+    }
+    return _librariesByName;
+  }
 
   Map<Uri, LibraryMirror> get libraries {
     if (_cachedLibraries != null) return _cachedLibraries;