Update version.dart to fetch the last changed revision of the root directory.

tools/release/version.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This file contains functionality for getting dart version numbers using
  * our standard version construction method. Systems that does not include this
  * file should emulate the structure for revision numbers that we have here.
  *
  * The version number of a dart build is constructed as follows:
@@ skipping 104 matching lines @@
   String getExecutableSuffix() {
     if (Platform.operatingSystem == 'windows') {
       return '.bat';
     }
     return '';
   }
 
   int getRevisionFromSvnInfo(String info) {
     if (info == null || info == '') return 0;
     var lines = info.split("\n");
-    RegExp exp = const RegExp(r"Revision: (\d*)");
+    RegExp exp = const RegExp(r"Last Changed Rev: (\d*)");
     for (var line in lines) {
       if (exp.hasMatch(line)) {
         String revisionString = (exp.firstMatch(line).group(1));
         try {
           return int.parse(revisionString);
         } catch(e) {
           return 0;
         }
       }
     }
     return 0;
   }
 
   Future<int> getRevision() {
     if (repositoryType == RepositoryType.UNKNOWN) {
       return new Future.immediate(0);
     }
     var isSvn = repositoryType == RepositoryType.SVN;
     var command = isSvn ? "svn" : "git";
     command = "$command${getExecutableSuffix()}";
     var arguments = isSvn ? ["info"] : ["svn", "info"];
-    return Process.run(command, arguments).transform((result) {
+    ProcessOptions options = new ProcessOptions();
+    // Run the command from the root to get the last changed revision for this
+    // "branch". Since we have both trunk and bleeding edge in the same
+    // repository and since we always build TOT we need this to get the
+    // right version number.
+    Path root =
+        new Path.fromNative(_versionFileName).directoryPath.directoryPath;
+    options.workingDirectory = root.toNativePath();
+    return Process.run(command, arguments, options).transform((result) {
       if (result.exitCode != 0) {
         return 0;
       }
       return getRevisionFromSvnInfo(result.stdout);
     });
   }
 
   bool isProductionBuild(String username) {
     return username == "chrome-bot";
   }
@@ skipping 29 matching lines @@
   static RepositoryType guessType() {
     if (new Directory(".svn").existsSync()) return RepositoryType.SVN;
     if (new Directory(".git").existsSync()) return RepositoryType.GIT;
     return RepositoryType.UNKNOWN;
   }
 
   String toString() => name;
 
   final String name;
 }