Move mojo and mojom from mojo/public/dart to mojo/dart/packages

mojo/dart/packages/mojom/lib/src/mojom_finder.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 part of generate;
 
 class PackageInfo {
   final String name;
   final Directory packageDir;
   final Directory importDir;
@@ skipping 100 matching lines @@
     log.info("Looking for dart package: $packagePath");
     if (await packageDir.exists()) {
       return packageDir;
     } else {
       log.info("$packagePath not found");
     }
   }
 
   bool _shouldSkip(File f) => containsPrefix(f.path, _skip);
 }