New verbose flag for the dart command line analyzer

pkg/analyzer/lib/src/analyzer_impl.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.
 
 library analyzer_impl;
 
 import 'dart:async';
 
 import 'dart:io';
 
@@ skipping 141 matching lines @@
         packageDirectory = getPackageDirectoryFor(sourceFile);
       }
       if (packageDirectory != null) {
         resolvers.add(new PackageUriResolver([packageDirectory]));
       }
     }
     sourceFactory = new SourceFactory(resolvers);
     context = AnalysisEngine.instance.createAnalysisContext();
     context.sourceFactory = sourceFactory;
     // Uncomment the following to have errors reported on stdout and stderr
-//    AnalysisEngine.instance.logger = new StdLogger();
+    if (options.verbose) {
+      AnalysisEngine.instance.logger = new StdLogger();
+    }
 
     // set options for context
     AnalysisOptionsImpl contextOptions = new AnalysisOptionsImpl();
     contextOptions.cacheSize = _MAX_CACHE_SIZE;
     contextOptions.hint = !options.disableHints;
     context.analysisOptions = contextOptions;
 
     // Create and add a ChangeSet
     ChangeSet changeSet = new ChangeSet();
     changeSet.addedSource(source);
@@ skipping 108 matching lines @@
   @override
   void logInformation(String message) {
     stdout.writeln(message);
   }
 
   @override
   void logInformation2(String message, Exception exception) {
     stdout.writeln(message);
   }
 }