Don't allow package:-URIs as package locations when creating .packages file.

lib/discovery.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 package_config.discovery;
 
 import "dart:async";
 import "dart:io";
 import "dart:typed_data" show Uint8List;
 
@@ skipping 161 matching lines @@
   assert(location is Directory);
   return new FilePackagesDirectoryPackages(location);
 }
 
 /// Finds a package resolution strategy for a Dart script.
 ///
 /// The [nonFileUri] points to either a Dart script or the directory of the
 /// script.
 /// The [nonFileUri] should not be a `file:` URI since the algorithm for
 /// finding a package resolution strategy is more elaborate for `file:` URIs.
-/// In that case, use [findPackagesFile].
+/// In that case, use [findPackagesFromFile].
 ///
 /// This function first tries to locate a `.packages` file in the [nonFileUri]
 /// directory. If that is not found, it instead assumes a `packages/` directory
 /// in the same place.
 ///
 /// By default, this function only works for `http:` and `https:` URIs.
 /// To support other schemes, a loader must be provided, which is used to
 /// try to load the `.packages` file. The loader should return the contents
 /// of the requested `.packages` file as bytes, which will be assumed to be
 /// UTF-8 encoded.
@@ skipping 26 matching lines @@
     totalLength += list.length;
   }
   Uint8List result = new Uint8List(totalLength);
   int offset = 0;
   for (List<int> contentPart in splitContent) {
     result.setRange(offset, offset + contentPart.length, contentPart);
     offset += contentPart.length;
   }
   return result;
 }