Turn on using SDK summaries in the command line analyzer.

pkg/analyzer_cli/lib/src/driver.dart

 // Copyright (c) 2015, 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_cli.src.driver;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 570 matching lines @@
     }
     return errorSeverity;
   }
 
   void _setupEnv(CommandLineOptions options) {
     // In batch mode, SDK is specified on the main command line rather than in
     // the command lines sent to stdin.  So process it before deciding whether
     // to activate batch mode.
     if (sdk == null) {
       sdk = new DirectoryBasedDartSdk(new JavaFile(options.dartSdkPath));
+      sdk.useSummary = true;
       sdk.analysisOptions = createAnalysisOptionsForCommandLineOptions(options);
     }
     _isBatch = options.shouldBatch;
   }
 
   static AnalysisOptionsImpl createAnalysisOptionsForCommandLineOptions(
       CommandLineOptions options) {
     AnalysisOptionsImpl contextOptions = new AnalysisOptionsImpl();
     contextOptions.hint = !options.disableHints;
     contextOptions.enableStrictCallChecks = options.enableStrictCallChecks;
@@ skipping 176 matching lines @@
     for (var package in packages) {
       var packageName = path.basename(package.path);
       var realPath = package.resolveSymbolicLinksSync();
       result[packageName] = [
         PhysicalResourceProvider.INSTANCE.getFolder(realPath)
       ];
     }
     return result;
   }
 }