update ContextManager to support analysis option include directive

pkg/analysis_server/test/context_manager_test.dart

 // Copyright (c) 2014, 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 test.context.directory.manager;
 
 import 'dart:collection';
 
 import 'package:analysis_server/src/context_manager.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
+import 'package:analyzer/source/analysis_options_provider.dart';
 import 'package:analyzer/source/error_processor.dart';
 import 'package:analyzer/src/context/builder.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/services/lint.dart';
 import 'package:analyzer/src/task/options.dart'
@@ skipping 1904 matching lines @@
     await pumpEventQueue();
 
     // Verify defaults restored.
     expect(options.enableGenericMethods, isFalse);
     expect(lints, hasLength(1));
     expect(lints.first, new isInstanceOf<AvoidAs>());
     expect(errorProcessors, hasLength(1));
     expect(getProcessor(missing_return).severity, isNull);
   }
 
+  test_analysis_options_include() async {
+    // Create files.
+    String libPath = newFolder([projPath, ContextManagerTest.LIB_NAME]);
+    newFile([libPath, 'main.dart']);
+    String sdkExtPath = newFolder([projPath, 'sdk_ext']);
+    newFile([sdkExtPath, 'entry.dart']);
+    String sdkExtSrcPath = newFolder([projPath, 'sdk_ext', 'src']);
+    newFile([sdkExtSrcPath, 'part.dart']);
+    // Setup analysis options file which includes another options file.
+    newFile(
+        [projPath, optionsFileName],
+        r'''
+include: other_options.yaml
+''');
+    newFile(
+        [projPath, 'other_options.yaml'],
+        r'''
+analyzer:
+  language:
+    enableGenericMethods: true
+  errors:
+    unused_local_variable: false
+linter:
+  rules:
+    - camel_case_types
+''');
+    // Setup context.
+    manager.setRoots(<String>[projPath], <String>[], <String, String>{});
+    await pumpEventQueue();
+
+    // Verify options were set.
+    expect(options.enableGenericMethods, isTrue);
+    expect(errorProcessors, hasLength(1));
+    expect(lints, hasLength(1));
+    expect(lints[0].name, 'camel_case_types');
+  }
+
   test_analysis_options_parse_failure() async {
     // Create files.
     String libPath = newFolder([projPath, ContextManagerTest.LIB_NAME]);
     newFile([libPath, 'main.dart']);
     String sdkExtPath = newFolder([projPath, 'sdk_ext']);
     newFile([sdkExtPath, 'entry.dart']);
     String sdkExtSrcPath = newFolder([projPath, 'sdk_ext', 'src']);
     newFile([sdkExtSrcPath, 'part.dart']);
     // Setup analysis options file with ignore list.
     newFile(
@@ skipping 819 matching lines @@
 class TestUriResolver extends UriResolver {
   Map<Uri, Source> uriMap;
 
   TestUriResolver(this.uriMap);
 
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     return uriMap[uri];
   }
 }