Add LibraryLoader.resetAsync.

dart/pkg/dart2js_incremental/lib/caching_compiler.dart

 // Copyright (c) 2013, 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.
 
 part of dart2js_incremental;
 
 /// Do not call this method directly. It will be made private.
 // TODO(ahe): Make this method private.
-Compiler reuseCompiler(
+Future<Compiler> reuseCompiler(
     {DiagnosticHandler diagnosticHandler,
      CompilerInputProvider inputProvider,
      CompilerOutputProvider outputProvider,
      List<String> options: const [],
      Compiler cachedCompiler,
      Uri libraryRoot,
      Uri packageRoot,
      bool packagesAreImmutable: false,
      Map<String, dynamic> environment,
-     bool reuseLibrary(LibraryElement library)}) {
+     Future<bool> reuseLibrary(LibraryElement library)}) {
   UserTag oldTag = new UserTag('_reuseCompiler').makeCurrent();
   if (libraryRoot == null) {
     throw 'Missing libraryRoot';
   }
   if (inputProvider == null) {
     throw 'Missing inputProvider';
   }
   if (diagnosticHandler == null) {
     throw 'Missing diagnosticHandler';
   }
@@ skipping 18 matching lines @@
       } else if (compiler.compilerWasCancelled) {
         print('Unable to reuse compiler due to cancel.');
       } else if (compiler.enqueuer.resolution.hasEnqueuedReflectiveElements) {
         print('Unable to reuse compiler due to dart:mirrors.');
       } else if (compiler.deferredLoadTask.isProgramSplit) {
         print('Unable to reuse compiler due to deferred loading.');
       } else {
         print('Unable to reuse compiler.');
       }
     }
-    compiler = new Compiler(
-        inputProvider,
-        outputProvider,
-        diagnosticHandler,
-        libraryRoot,
-        packageRoot,
-        options,
-        environment);
+    oldTag.makeCurrent();
+    return new Future.value(
+        new Compiler(
+            inputProvider,
+            outputProvider,
+            diagnosticHandler,
+            libraryRoot,
+            packageRoot,
+            options,
+            environment));
   } else {
     for (final task in compiler.tasks) {
       if (task.watch != null) {
         task.watch.reset();
       }
     }
     compiler
         ..outputProvider = outputProvider
         ..provider = inputProvider
         ..handler = diagnosticHandler
@@ skipping 55 matching lines @@
         ..precompiledFunction.clear()
         ..precompiledConstructorNames.clear()
         ..hasMakeConstantList = false
         ..elementDescriptors.clear();
 
     backend
         ..preMirrorsMethodCount = 0;
 
     if (reuseLibrary == null) {
       reuseLibrary = (LibraryElement library) {
-        return
+        return new Future.value(
             library.isPlatformLibrary ||
-            (packagesAreImmutable && library.isPackageLibrary);
+            (packagesAreImmutable && library.isPackageLibrary));
       };
     }
-    compiler.libraryLoader.reset(reuseLibrary: reuseLibrary);
+    return compiler.libraryLoader.resetAsync(reuseLibrary).then((_) {
+      oldTag.makeCurrent();
+      return compiler;
+    });
   }
-  oldTag.makeCurrent();
-  return compiler;
 }