Only generate summaries in tests when necessary

pkg/analyzer/test/src/context/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 analyzer.test.src.context.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/cache.dart';
 import 'package:analyzer/src/context/context.dart';
@@ skipping 333 matching lines @@
 
   @override
   final List<SdkLibrary> sdkLibraries;
 
   /**
    * The cached linked bundle of the SDK.
    */
   PackageBundle _bundle;
 
   MockSdk(
-      {bool buildSummaries: true,
+      {bool generateSummaryFiles: false,
       bool dartAsync: true,
       resource.MemoryResourceProvider resourceProvider})
       : provider = resourceProvider ?? new resource.MemoryResourceProvider(),
         sdkLibraries = dartAsync ? _LIBRARIES : [_LIB_CORE],
         uriMap = dartAsync ? FULL_URI_MAP : NO_ASYNC_URI_MAP {
     for (_MockSdkLibrary library in sdkLibraries) {
       provider.newFile(provider.convertPath(library.path), library.content);
       library.parts.forEach((String path, String content) {
         provider.newFile(provider.convertPath(path), content);
       });
     }
     provider.newFile(
         provider.convertPath(
             '$sdkRoot/lib/_internal/sdk_library_metadata/lib/libraries.dart'),
         librariesContent);
-    if (buildSummaries) {
+    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
   AnalysisContextImpl get context {
@@ skipping 43 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 83 matching lines @@
 
   @override
   AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
     if (factory == null) {
       return super.createCacheFromSourceFactory(factory);
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }