Support --persistent_worker flag in --build-mode.

pkg/analyzer_cli/lib/src/driver.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 analyzer_cli.src.driver;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 226 matching lines @@
     if (!options.machineFormat) {
       stats.print(outSink);
     }
 
     return allResult;
   }
 
   /// Perform analysis in build mode according to the given [options].
   ErrorSeverity _buildModeAnalyze(CommandLineOptions options) {
     return _analyzeAllTag.makeCurrentWhile(() {
-      return new BuildMode(options, stats).analyze();
+      if (options.buildModePersistentWorker) {
+        new WorkerLoop.std().run();
+      } else {
+        return new BuildMode(options, stats).analyze();
+      }
     });
   }
 
   /// Determine whether the context created during a previous call to
   /// [_analyzeAll] can be re-used in order to analyze using [options].
   bool _canContextBeReused(CommandLineOptions options) {
     // TODO(paulberry): add a command-line option that disables context re-use.
     if (_context == null) {
       return false;
     }
@@ skipping 521 matching lines @@
     for (var package in packages) {
       var packageName = path.basename(package.path);
       var realPath = package.resolveSymbolicLinksSync();
       result[packageName] = [
         PhysicalResourceProvider.INSTANCE.getFolder(realPath)
       ];
     }
     return result;
   }
 }