New verbose flag for the dart command line analyzer

pkg/analyzer/lib/options.dart

Index: pkg/analyzer/lib/options.dart
diff --git a/pkg/analyzer/lib/options.dart b/pkg/analyzer/lib/options.dart
index bdb58f04636dde83b989b98f49ec013e3d6ff513..3aa4dd37a34a069aba2b5b21863bb813f84daf2c 100644
--- a/pkg/analyzer/lib/options.dart
+++ b/pkg/analyzer/lib/options.dart
@@ -51,6 +51,9 @@ class CommandLineOptions {
   /** The source files to analyze */
   final List<String> sourceFiles;
 
+  /** Whether to log additional analysis messages and exceptions */
+  final bool log;
+
   /**
    * Initialize options from the given parsed [args].
    */
@@ -66,6 +69,7 @@ class CommandLineOptions {
       warningsAreFatal = args['fatal-warnings'],
       dartSdkPath = args['dart-sdk'],
       packageRootPath = args['package-root'],
+      log = args['log'],
       sourceFiles = args.rest;
 
   /**
@@ -128,7 +132,9 @@ class CommandLineOptions {
       ..addFlag('show-sdk-warnings', help: 'Show warnings from SDK imports (deprecated)',
           defaultsTo: false, negatable: false)
       ..addFlag('help', abbr: 'h', help: 'Display this help message',
-          defaultsTo: false, negatable: false);
+          defaultsTo: false, negatable: false)
+      ..addFlag('log', help: 'Log additional messages and exceptions',
+        defaultsTo: false, negatable: false, hide: true);
 
     try {
       // TODO(scheglov) https://code.google.com/p/dart/issues/detail?id=11061
@@ -206,10 +212,10 @@ class _CommandLineParser {
    * See [ArgParser.addFlag()].
    */
   void addFlag(String name, {String abbr, String help, bool defaultsTo: false,
-      bool negatable: true, void callback(bool value)}) {
+      bool negatable: true, void callback(bool value), bool hide: false}) {
     _knownFlags.add(name);
     _parser.addFlag(name, abbr: abbr, help: help, defaultsTo: defaultsTo,
-        negatable: negatable, callback: callback);
+        negatable: negatable, callback: callback, hide: hide);
   }
 
   /**