Add compile_from_dill test

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.js_emitter.full_emitter;
 
 import 'dart:collection' show HashMap;
 import 'dart:convert';
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
@@ skipping 1008 matching lines @@
       uri = library.canonicalUri;
       if (uri.scheme == 'file' && compiler.options.outputUri != null) {
         uri =
             relativize(compiler.options.outputUri, library.canonicalUri, false);
       }
     }
 
     String libraryName = (!compiler.options.enableMinification ||
             backend.mirrorsData.mustRetainLibraryNames)
         // TODO(johnniwinther): Support library names for entities.
-        ? library is LibraryElement ? library.libraryName : library.name
+        ? library is LibraryElement ? library.libraryName : ''
         : "";
 
     jsAst.Fun metadata =
         task.metadataCollector.buildLibraryMetadataFunction(library);
 
     ClassBuilder descriptor = libraryDescriptors[fragment][library];
 
     jsAst.ObjectInitializer initializer;
     if (descriptor == null) {
       // Nothing of the library was emitted.
@@ skipping 856 matching lines @@
         output.close();
       }
 
       hunkHashes[outputUnit] = hash;
     }
     return hunkHashes;
   }
 
   jsAst.Comment buildGeneratedBy() {
     List<String> options = [];
-    if (compiler.commonElements.mirrorsLibrary != null) options.add('mirrors');
+    if (compiler.commonElements.mirrorsLibrary != null &&
+        !compiler.options.loadFromDill) {
+      // TODO(johnniwinther): Add `isMirrorsUsed` to [BackendData] instead
+      // of checking `mirrorsLibrary`.
+      options.add('mirrors');
+    }
     if (compiler.options.useContentSecurityPolicy) options.add("CSP");
     return new jsAst.Comment(generatedBy(compiler, flavor: options.join(", ")));
   }
 
   void outputDeferredMap() {
     Map<String, dynamic> mapping = new Map<String, dynamic>();
     // Json does not support comments, so we embed the explanation in the
     // data.
     mapping["_comment"] = "This mapping shows which compiled `.js` files are "
         "needed for a given deferred library import.";
     mapping.addAll(compiler.deferredLoadTask.computeDeferredMap());
     compiler.outputProvider(
         compiler.options.deferredMapUri.path, '', OutputType.info)
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }