update DDC to use analyzer extractDefinedVariables

pkg/dev_compiler/lib/src/analyzer/context.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.
 
 import 'package:args/args.dart' show ArgParser, ArgResults;
 import 'package:analyzer/file_system/file_system.dart'
     show ResourceProvider, ResourceUriResolver;
 import 'package:analyzer/file_system/physical_file_system.dart'
     show PhysicalResourceProvider;
 import 'package:analyzer/source/custom_resolver.dart';
@@ skipping 157 matching lines @@
   return sdk;
 }
 
 /// Creates a [DartUriResolver] that uses the SDK at the given [sdkPath].
 DartUriResolver createSdkPathResolver(String sdkSummaryPath, String sdkPath) {
   var sdk = (sdkSummaryPath != null)
       ? new SummaryBasedDartSdk(sdkSummaryPath, true)
       : _createFolderBasedDartSdk(sdkPath);
   return new DartUriResolver(sdk);
 }
-
-List<String> parseDeclaredVariables(
-    List<String> args, Map<String, String> declaredVars) {
-  var count = args.length;
-  var remainingArgs = <String>[];
-  for (int i = 0; i < count; i++) {
-    var arg = args[i];
-    if (arg == '--') {
-      while (i < count) {
-        remainingArgs.add(args[i++]);
-      }
-    } else if (arg.startsWith("-D")) {
-      // The format for defined variables is:
-      //     -D<name>=<value>
-      var parts = arg.substring(2).split('=');
-      declaredVars[parts[0]] = parts.length > 1 ? parts[1] : '';
-    } else {
-      remainingArgs.add(arg);
-    }
-  }
-  return remainingArgs;
-}