fix readability regressions from previous block-scope CL

lib/src/compiler.dart

Index: lib/src/compiler.dart
diff --git a/lib/src/compiler.dart b/lib/src/compiler.dart
index f5a0aecf82f7936cfba2fab49069c0eab25b1b64..1723d4c5fb58fb83a8a694452cf0c64c0b5c666c 100644
--- a/lib/src/compiler.dart
+++ b/lib/src/compiler.dart
@@ -173,20 +173,6 @@ class BatchCompiler extends AbstractCompiler {
     }
 
     if (_jsGen != null) {
-      // TODO(jmesserly): full incremental support would avoid checking as well,
-      // however, we'd lose compiler messages in that case.
-
-      // Note: analyzer's modification stamp is millisecondsSinceEpoch
-      int lastModifyTime = unitElements
-          .map((e) => context.getModificationStamp(e.source))
-          .reduce(math.max);
-      var outFile = new File(getOutputPath(library.source.uri));
-      if (outFile.existsSync() &&
-          outFile.lastModifiedSync().millisecondsSinceEpoch >= lastModifyTime) {
-        // Output already up to date.
-        return;
-      }
-
       var unit = units.first;
       var parts = units.skip(1).toList();
       _jsGen.generateLibrary(new LibraryUnit(unit, parts));