Snapshot DDC trained on itself

pkg/dev_compiler/lib/src/compiler/command.dart

Index: pkg/dev_compiler/lib/src/compiler/command.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/command.dart b/pkg/dev_compiler/lib/src/compiler/command.dart
index 6170f6d85f7631e774f687cf7086b235ba7bd109..d037eac28ca296ae92375b42c4ed6f68a3e46f24 100644
--- a/pkg/dev_compiler/lib/src/compiler/command.dart
+++ b/pkg/dev_compiler/lib/src/compiler/command.dart
@@ -161,14 +161,14 @@ void _compile(ArgResults argResults, AnalyzerOptions analyzerOptions,
 
   var libraryRoot = argResults['library-root'] as String;
   if (libraryRoot != null) {
-    libraryRoot = path.absolute(libraryRoot);
+    libraryRoot = path.canonicalize(libraryRoot);
   } else {
     libraryRoot = Directory.current.path;
   }
   var moduleRoot = argResults['module-root'] as String;
   String modulePath;
   if (moduleRoot != null) {
-    moduleRoot = path.absolute(moduleRoot);
+    moduleRoot = path.canonicalize(moduleRoot);
     if (!path.isWithin(moduleRoot, firstOutPath)) {
       _usageException('Output file $firstOutPath must be within the module '
           'root directory $moduleRoot');