Disable mirrors metadata gen by default

lib/src/compiler/compiler.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:collection' show HashSet;
 import 'package:args/args.dart' show ArgParser, ArgResults;
 import 'package:analyzer/analyzer.dart'
     show
         AnalysisError,
         CompilationUnit,
@@ skipping 166 matching lines @@
 
   /// Which module format to support.
   /// Currently 'es6' and 'legacy' are supported.
   final ModuleFormat moduleFormat;
 
   const CompilerOptions(
       {this.sourceMap: true,
       this.sourceMapComment: true,
       this.summarizeApi: true,
       this.unsafeForceCompile: false,
-      this.emitMetadata: true,
+      this.emitMetadata: false,
       this.closure: false,
       this.destructureNamedParams: false,
       this.moduleFormat: ModuleFormat.legacy});
 
   CompilerOptions.fromArguments(ArgResults args)
       : sourceMap = args['source-map'],
         sourceMapComment = args['source-map-comment'],
         summarizeApi = args['summarize'],
         unsafeForceCompile = args['unsafe-force-compile'],
         emitMetadata = args['emit-metadata'],
@@ skipping 12 matching lines @@
         help: 'module pattern to emit',
         allowed: ['es6', 'legacy', 'node'],
         allowedHelp: {
           'es6': 'es6 modules',
           'legacy': 'a custom format used by dartdevc, similar to AMD',
           'node': 'node.js modules (https://nodejs.org/api/modules.html)'
         },
         defaultsTo: 'legacy')
     ..addFlag('emit-metadata',
         help: 'emit metadata annotations queriable via mirrors',
-        defaultsTo: true)
+        defaultsTo: false)
     ..addFlag('closure-experimental',
         help: 'emit Closure Compiler-friendly code (experimental)',
         defaultsTo: false)
     ..addFlag('destructure-named-params',
         help: 'Destructure named parameters', defaultsTo: false)
     ..addFlag('unsafe-force-compile',
         help: 'Compile code even if it has errors. ಠ_ಠ\n'
             'This has undefined behavior!',
         defaultsTo: false);
 }
@@ skipping 77 matching lines @@
   }
 }
 
 /// (Public for tests) the error code used when a part is missing.
 final missingPartErrorCode = const CompileTimeErrorCode(
     'MISSING_PART', 'The part was not supplied as an input to the compiler.');
 
 /// (Public for tests) the error code used when a part is unused.
 final unusedPartWarningCode = const StaticWarningCode(
     'UNUSED_PART', 'The part was not used by any libraries being compiled.');