fix #27784 and fix #27785, fromEnvironment constants in DDC

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 28 matching lines @@
   final List<String> packagePaths;
 
   /// Path to the dart-sdk. Null if `useMockSdk` is true or if the path couldn't
   /// be determined
   final String dartSdkPath;
 
   /// Path to the dart-sdk summary.  If this is set, it will be used in favor
   /// of the unsummarized one.
   final String dartSdkSummaryPath;
 
+  /// Defined variables used by `bool.fromEnvironment` etc.
+  final Map<String, String> declaredVariables;
+
   AnalyzerOptions(
       {this.summaryPaths: const [],
       String dartSdkPath,
       this.dartSdkSummaryPath,
       this.customUrlMappings: const {},
       this.packageRoot: null,
-      this.packagePaths: const []})
+      this.packagePaths: const [],
+      this.declaredVariables: const {}})
       : dartSdkPath = dartSdkPath ?? getSdkDir().path;
 
-  factory AnalyzerOptions.fromArguments(ArgResults args) {
+  factory AnalyzerOptions.fromArguments(
+      ArgResults args, Map<String, String> declaredVariables) {
     var sdkPath = args['dart-sdk'] ?? getSdkDir().path;
     var sdkSummaryPath = args['dart-sdk-summary'];
 
     if (sdkSummaryPath == null) {
       sdkSummaryPath = path.join(sdkPath, 'lib', '_internal', 'ddc_sdk.sum');
     } else if (sdkSummaryPath == 'build') {
       // For building the SDK, we explicitly set the path to none.
       sdkSummaryPath = null;
     }
 
     return new AnalyzerOptions(
         summaryPaths: args['summary'] as List<String>,
         dartSdkPath: sdkPath,
         dartSdkSummaryPath: sdkSummaryPath,
         customUrlMappings: _parseUrlMappings(args['url-mapping']),
         packageRoot: args['package-root'],
-        packagePaths: (args['package-paths'] as String)?.split(',') ?? []);
+        packagePaths: (args['package-paths'] as String)?.split(',') ?? [],
+        declaredVariables: declaredVariables);
   }
 
   /// Whether to resolve 'package:' uris using the multi-package resolver.
   bool get useMultiPackage => packagePaths.isNotEmpty;
 
   static void addArguments(ArgParser parser) {
     parser
       ..addOption('summary',
           abbr: 's', help: 'summary file(s) to include', allowMultiple: true)
       ..addOption('dart-sdk',
@@ skipping 93 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;
+}