Split installing a package locally from symlinking to it.

sdk/lib/_internal/pub/lib/src/source/path.dart

 // Copyright (c) 2013, 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 pub.source.path;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as path;
 
@@ skipping 15 matching lines @@
     });
   }
 
   bool descriptionsEqual(description1, description2) {
     // Compare real paths after normalizing and resolving symlinks.
     var path1 = canonicalize(description1["path"]);
     var path2 = canonicalize(description2["path"]);
     return path1 == path2;
   }
 
-  /// Create a symlink from the source path directly to the destination
-  /// directory.
-  Future get(PackageId id, String destination) {
+  /// Path dependencies are already local.
+  Future ensureLocal(PackageId id) => new Future.value();
+
+  Future get(PackageId id, String symlink) {
     return syncFuture(() {
       var dir = _validatePath(id.name, id.description);
-      createPackageSymlink(id.name, dir, destination,
+      createPackageSymlink(id.name, dir, symlink,
           relative: id.description["relative"]);
     });
   }
 
   Future<String> getDirectory(PackageId id) =>
       newFuture(() => _validatePath(id.name, id.description));
 
   /// Parses a path dependency.
   ///
   /// This takes in a path string and returns a map. The "path" key will be the
@@ skipping 81 matching lines @@
 
     if (fileExists(dir)) {
       fail('Path dependency for package $name must refer to a directory, '
            'not a file. Was "$dir".');
     }
 
     throw new PackageNotFoundException(
         'Could not find package $name at "$dir".');
   }
 }