Fixes in codegen and test script

lib/src/utils.dart

Index: lib/src/utils.dart
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index a30473d5290f12642b1e68ccc6c3b0ba57396915..9056f861250c79733a70ea2ab7dde10016f756fc 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -37,7 +37,16 @@ bool isDartPrivateLibrary(LibraryElement library) {
 /// meaningful rules enforced.
 String canonicalLibraryName(LibraryElement library) {
   var uri = library.source.uri;
-  return path.basenameWithoutExtension(uri.pathSegments.last);
+  var name = path.basenameWithoutExtension(uri.pathSegments.last);
+  return _toIdentifier(name);
+}
+
+/// Sanitize [name] to make it into a valid identifier.
+String _toIdentifier(String name) {
+  if (name.length == 0) return r'$';
+  name = name.replaceAllMapped(new RegExp(r'[^A-Za-z_$0-9]'), (c) => '_');

[Jennifer Messerly, 2015/03/11 20:28:54]

are we worried about collisions? would an escaping scheme be better? or fall
back to library's name?

[Siggi Cherem (dart-lang), 2015/03/11 23:27:22]

Good point - went with an escaping scheme.

+  if (name.startsWith(new RegExp('[0-9]'))) return '\$$name';
+  return name;

[Jennifer Messerly, 2015/03/11 20:28:54]

do we need to exclude JS keywords if generating JS? (e.g. `switch.js`)

[Siggi Cherem (dart-lang), 2015/03/11 23:27:22]

Good point - I made isJsKeyword in js_ast public for this purpose and moved to a
separate library. Not sure if we are trying to minimize changes there though.

[Jennifer Messerly, 2015/03/11 23:48:00]

Generally I've been sticking to adds. But that was a method I added, so no
worries about moving it :)

 }
 
 /// Returns all libraries transitively imported or exported from [start].