Add DartSdk.getLinkedBundle() and use it in PubSummaryManager.

pkg/analyzer/lib/src/generated/sdk_io.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.
 
 @deprecated
 library analyzer.src.generated.sdk_io;
 
 import 'dart:collection';
 import 'dart:io';
 
@@ skipping 620 matching lines @@
     JavaFile libDir = new JavaFile.relative(dir, libraryName);
     JavaFile docFile =
         new JavaFile.relative(libDir, "$libraryName$_DOC_FILE_SUFFIX");
     if (docFile.exists()) {
       return docFile;
     }
     return null;
   }
 
   @override
+  PackageBundle getLinkedBundle() => null;
+
+  @override
   String getRelativePathFromFile(JavaFile file) {
     String filePath = file.getAbsolutePath();
     String libPath = libraryDirectory.getAbsolutePath();
     if (!filePath.startsWith("$libPath${JavaFile.separator}")) {
       return null;
     }
     return filePath.substring(libPath.length + 1);
   }
 
   /**
@@ skipping 138 matching lines @@
     SdkLibrariesReader_LibraryBuilder libraryBuilder =
         new SdkLibrariesReader_LibraryBuilder(_useDart2jsPaths);
     // If any syntactic errors were found then don't try to visit the AST
     // structure.
     if (!errorListener.errorReported) {
       unit.accept(libraryBuilder);
     }
     return libraryBuilder.librariesMap;
   }
 }