Fix polymer tests and a couple bugs

pkg/polymer/test/build/linter_test.dart

Index: pkg/polymer/test/build/linter_test.dart
diff --git a/pkg/polymer/test/build/linter_test.dart b/pkg/polymer/test/build/linter_test.dart
index ab6ff85f3a0241e9daf4cf4cc66b994980c57609..e302915c0217ee17d6915d1d1becd362457a0f44 100644
--- a/pkg/polymer/test/build/linter_test.dart
+++ b/pkg/polymer/test/build/linter_test.dart
@@ -460,6 +460,8 @@ void main() {
 _testLinter(String name, Map inputFiles, List outputMessages) {
   var linter = new Linter(new TransformOptions());
   var outputFiles = {};
-  inputFiles.forEach((k, v) => outputFiles[k] = v);
+  if (outputMessages.every((m) => m.startsWith('warning:'))) {
+    inputFiles.forEach((k, v) => outputFiles[k] = v);
+  }
   testPhases(name, [[linter]], inputFiles, outputFiles, outputMessages);
 }