Use sdk summaries in front_end/kernel_generator.

pkg/kernel/lib/analyzer/loader.dart

Index: pkg/kernel/lib/analyzer/loader.dart
diff --git a/pkg/kernel/lib/analyzer/loader.dart b/pkg/kernel/lib/analyzer/loader.dart
index ae169260ea99300157ce6e8bd8f436305648dfc9..b007d9fa33f723eb7defeeea09f3ff9f7f32fed9 100644
--- a/pkg/kernel/lib/analyzer/loader.dart
+++ b/pkg/kernel/lib/analyzer/loader.dart
@@ -16,6 +16,7 @@ import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source_io.dart';
+import 'package:analyzer/src/summary/summary_sdk.dart';
 import 'package:kernel/application_root.dart';
 import 'package:package_config/discovery.dart';
 import 'package:package_config/packages.dart';
@@ -34,16 +35,29 @@ class DartOptions {
 
   /// True if the Dart SDK should be loaded in strong mode.
   bool strongModeSdk;
+
+  /// Path to the sdk sources, ignored if sdkSummary is provided.
   String sdk;
+
+  /// Path to a summary of the sdk sources.
+  String sdkSummary;
+
+  /// Path to the `.packages` file.
   String packagePath;
+
+  /// Root used to relativize app file-urls, making them machine agnostic.
   ApplicationRoot applicationRoot;
+
   Map<Uri, Uri> customUriMappings;
+
+  /// Environment definitions provided via `-Dkey=value`.
   Map<String, String> declaredVariables;
 
   DartOptions(
       {bool strongMode: false,
       bool strongModeSdk,
       this.sdk,
+      this.sdkSummary,
       this.packagePath,
       ApplicationRoot applicationRoot,
       Map<Uri, Uri> customUriMappings,
@@ -763,7 +777,10 @@ AnalysisOptions createAnalysisOptions(bool strongMode) {
     ..enableSuperMixins = true;
 }
 
-DartSdk createDartSdk(String path, {bool strongMode}) {
+DartSdk createDartSdk(String path, {bool strongMode, bool isSummary}) {
+  if (isSummary) {
+    return new SummaryBasedDartSdk(path, strongMode);
+  }
   var resources = PhysicalResourceProvider.INSTANCE;
   return new FolderBasedDartSdk(resources, resources.getFolder(path))
     ..context
@@ -806,7 +823,9 @@ class CustomUriResolver extends UriResolver {
 
 AnalysisContext createContext(DartOptions options, Packages packages,
     {DartSdk dartSdk}) {
-  dartSdk ??= createDartSdk(options.sdk, strongMode: options.strongModeSdk);
+  bool fromSummary = options.sdkSummary != null;
+  dartSdk ??= createDartSdk(fromSummary ? options.sdkSummary : options.sdk,
+      strongMode: options.strongModeSdk, isSummary: fromSummary);
 
   var resourceProvider = PhysicalResourceProvider.INSTANCE;
   var resourceUriResolver = new ResourceUriResolver(resourceProvider);