Fix names of map files in the startup emitter.

pkg/compiler/lib/src/js_emitter/startup_emitter/model_emitter.dart

 // Copyright (c) 2015, 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.startup_emitter.model_emitter;
 
 import 'dart:convert' show JsonEncoder;
 
 import '../../common.dart';
 
@@ skipping 68 matching lines @@
   // The full code that is written to each hunk part-file.
   final Map<Fragment, CodeOutput> outputBuffers = <Fragment, CodeOutput>{};
 
 
   JavaScriptBackend get backend => compiler.backend;
 
   /// For deferred loading we communicate the initializers via this global var.
   static const String deferredInitializersGlobal =
       r"$__dart_deferred_initializers__";
 
+  static const String partExtension = "part";
   static const String deferredExtension = "part.js";
 
   static const String typeNameProperty = r"builtin$cls";
 
   ModelEmitter(Compiler compiler, Namer namer, this.nativeEmitter,
                this.shouldGenerateSourceMap)
       : this.compiler = compiler,
         this.namer = namer {
     this.constantEmitter = new ConstantEmitter(
         compiler, namer, this.generateConstantReference,
@@ skipping 173 matching lines @@
 
     if (shouldGenerateSourceMap) {
       mainOutput.add(
           generateSourceMapTag(compiler.sourceMapUri, compiler.outputUri));
     }
 
     mainOutput.close();
 
     if (shouldGenerateSourceMap) {
       outputSourceMap(mainOutput, lineColumnCollector, '',
-      compiler.sourceMapUri, compiler.outputUri);
+          compiler.sourceMapUri, compiler.outputUri);
     }
   }
 
   // Writes the given [fragment]'s [code] into a file.
   //
   // Returns the deferred fragment's hash.
   //
   // Updates the shared [outputBuffers] field with the output.
   String writeDeferredFragment(DeferredFragment fragment, js.Expression code) {
     List<CodeOutputListener> outputListeners = <CodeOutputListener>[];
@@ skipping 36 matching lines @@
     String hash = hasher.getHash();
 
     // Now we copy the deferredInitializer.current into its correct hash.
     output.add('\n${deferredInitializersGlobal}["$hash"] = '
         '${deferredInitializersGlobal}.current');
 
     if (shouldGenerateSourceMap) {
       Uri mapUri, partUri;
       Uri sourceMapUri = compiler.sourceMapUri;
       Uri outputUri = compiler.outputUri;
+      String partName = "$hunkPrefix.$partExtension";
+      String hunkFileName = "$hunkPrefix.$deferredExtension";
 
       if (sourceMapUri != null) {
-        String mapFileName =
-            hunkPrefix + deferredExtension + ".map";
+        String mapFileName = hunkFileName + ".map";
         List<String> mapSegments = sourceMapUri.pathSegments.toList();
         mapSegments[mapSegments.length - 1] = mapFileName;
         mapUri = compiler.sourceMapUri.replace(pathSegments: mapSegments);
       }
 
       if (outputUri != null) {
-        String hunkFileName = hunkPrefix + deferredExtension;
         List<String> partSegments = outputUri.pathSegments.toList();
         partSegments[partSegments.length - 1] = hunkFileName;
         partUri = compiler.outputUri.replace(pathSegments: partSegments);
       }
 
       output.add(generateSourceMapTag(mapUri, partUri));
       output.close();
-      outputSourceMap(output, lineColumnCollector, hunkPrefix, mapUri, partUri);
+      outputSourceMap(output, lineColumnCollector, partName, mapUri, partUri);
     } else {
       output.close();
     }
 
     return hash;
   }
 
   String generateSourceMapTag(Uri sourceMapUri, Uri fileUri) {
     if (sourceMapUri != null && fileUri != null) {
       String sourceMapFileName = relativize(fileUri, sourceMapUri, false);
@@ skipping 32 matching lines @@
     // 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.deferredMapUri.path, 'deferred_map')
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }