Only generate summaries in tests when necessary

pkg/analysis_server/test/mock_sdk.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 testing.mock_sdk;
 
 import 'package:analyzer/file_system/file_system.dart' as resource;
 import 'package:analyzer/file_system/memory_file_system.dart' as resource;
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ skipping 251 matching lines @@
   /**
    * The [AnalysisContext] which is used for all of the sources.
    */
   InternalAnalysisContext _analysisContext;
 
   /**
    * The cached linked bundle of the SDK.
    */
   PackageBundle _bundle;
 
-  MockSdk({resource.ResourceProvider resourceProvider})
+  MockSdk(
+      {bool generateSummaryFiles: false,
+      resource.ResourceProvider resourceProvider})
       : provider = resourceProvider ?? new resource.MemoryResourceProvider() {
     LIBRARIES.forEach((SdkLibrary library) {
       provider.newFile(library.path, (library as MockSdkLibrary).content);
     });
     provider.newFile(
         provider.convertPath(
             '/lib/_internal/sdk_library_metadata/lib/libraries.dart'),
         librariesContent);
-    List<int> bytes = _computeLinkedBundleBytes();
-    provider.newFileWithBytes(
-        provider.convertPath('/lib/_internal/spec.sum'), bytes);
-    provider.newFileWithBytes(
-        provider.convertPath('/lib/_internal/strong.sum'), bytes);
+    if (generateSummaryFiles) {
+      List<int> bytes = _computeLinkedBundleBytes();
+      provider.newFileWithBytes(
+          provider.convertPath('/lib/_internal/spec.sum'), bytes);
+      provider.newFileWithBytes(
+          provider.convertPath('/lib/_internal/strong.sum'), bytes);
+    }
   }
 
   @override
   AnalysisContext get context {
     if (_analysisContext == null) {
       _analysisContext = new SdkAnalysisContext(null);
       SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
       _analysisContext.sourceFactory = factory;
     }
     return _analysisContext;
@@ skipping 45 matching lines @@
           return null;
         }
       }
     }
     return null;
   }
 
   @override
   PackageBundle getLinkedBundle() {
     if (_bundle == null) {
-      _bundle = new PackageBundle.fromBuffer(_computeLinkedBundleBytes());
+      resource.File summaryFile =
+          provider.getFile(provider.convertPath('/lib/_internal/spec.sum'));
+      List<int> bytes;
+      if (summaryFile.exists) {
+        bytes = summaryFile.readAsBytesSync();
+      } else {
+        bytes = _computeLinkedBundleBytes();
+      }
+      _bundle = new PackageBundle.fromBuffer(bytes);
     }
     return _bundle;
   }
 
   @override
   SdkLibrary getSdkLibrary(String dartUri) {
     // getSdkLibrary() is only used to determine whether a library is internal
     // to the SDK.  The mock SDK doesn't have any internals, so it's safe to
     // return null.
     return null;
@@ skipping 62 matching lines @@
   bool get isShared => throw unimplemented;
 
   @override
   bool get isVmLibrary => throw unimplemented;
 
   UnimplementedError get unimplemented => new UnimplementedError();
 
   @override
   List<String> getPatches(int platform) => const <String>[];
 }