Add code to ProcessedOptions to fetch the SDK summary bundle.

pkg/front_end/test/src/base/processed_options_test.dart

 // Copyright (c) 2017, 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:async';
+
+import 'package:analyzer/src/summary/format.dart';
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/base/processed_options.dart';
 import 'package:path/path.dart' as pathos;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(ProcessedOptionsTest);
   });
 }
 
 @reflectiveTest
 class ProcessedOptionsTest {
   final fileSystem = new MemoryFileSystem(pathos.posix, Uri.parse('file:///'));
 
+  PackageBundleBuilder _mockSdkSummary;
+
+  PackageBundleBuilder get mockSdkSummary => _mockSdkSummary ??=
+      new PackageBundleBuilder(apiSignature: 'mock summary signature');
+
+  Future<Null> checkMockSummary(CompilerOptions raw) async {
+    var processed = new ProcessedOptions(raw);
+    var sdkSummary = await processed.getSdkSummary();
+    expect(sdkSummary.apiSignature, mockSdkSummary.apiSignature);
+  }
+
   test_compileSdk_false() {
     for (var value in [false, true]) {
       var raw = new CompilerOptions()..compileSdk = value;
       var processed = new ProcessedOptions(raw);
       expect(processed.compileSdk, value);
     }
   }
 
   test_fileSystem_noBazelRoots() {
     // When no bazel roots are specified, the filesystem should be passed
     // through unmodified.
     var raw = new CompilerOptions()..fileSystem = fileSystem;
     var processed = new ProcessedOptions(raw);
     expect(processed.fileSystem, same(fileSystem));
   }
 
+  test_getSdkSummary_sdkLocationProvided_noTrailingSlash() async {
+    var uri = Uri.parse('file:///sdk');
+    writeMockSummaryTo(Uri.parse('$uri/lib/_internal/strong.sum'));
+    checkMockSummary(new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..sdkRoot = uri);
+  }
+
+  test_getSdkSummary_sdkLocationProvided_spec() async {
+    var uri = Uri.parse('file:///sdk');
+    writeMockSummaryTo(Uri.parse('$uri/lib/_internal/spec.sum'));
+    checkMockSummary(new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..strongMode = false
+      ..sdkRoot = uri);
+  }
+
+  test_getSdkSummary_sdkLocationProvided_trailingSlash() async {
+    var uri = Uri.parse('file:///sdk');
+    writeMockSummaryTo(Uri.parse('$uri/lib/_internal/strong.sum'));
+    checkMockSummary(new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..sdkRoot = Uri.parse('$uri/'));
+  }
+
+  test_getSdkSummary_summaryLocationProvided() async {
+    var uri = Uri.parse('file:///sdkSummary');
+    writeMockSummaryTo(uri);
+    checkMockSummary(new CompilerOptions()
+      ..fileSystem = fileSystem
+      ..sdkSummary = uri);
+  }
+
   test_getUriResolver_explicitPackagesFile() async {
     // This .packages file should be ignored.
     fileSystem
         .entityForUri(Uri.parse('file:///.packages'))
         .writeAsStringSync('foo:bar\n');
     // This one should be used.
     fileSystem
         .entityForUri(Uri.parse('file:///explicit.packages'))
         .writeAsStringSync('foo:baz\n');
     var raw = new CompilerOptions()
@@ skipping 27 matching lines @@
     fileSystem
         .entityForUri(Uri.parse('file:///.packages'))
         .writeAsStringSync('foo:bar\n');
     var raw = new CompilerOptions()
       ..fileSystem = fileSystem
       ..packagesFileUri = new Uri();
     var processed = new ProcessedOptions(raw);
     var uriResolver = await processed.getUriResolver();
     expect(uriResolver.packages, isEmpty);
   }
+
+  void writeMockSummaryTo(Uri uri) {
+    fileSystem.entityForUri(uri).writeAsBytesSync(mockSdkSummary.toBuffer());
+  }
 }