diff --git a/dart_format.py b/dart_format.py
new file mode 100755
index 0000000..ee07efe
--- /dev/null
+++ b/dart_format.py
@@ -0,0 +1,58 @@
+#!/usr/bin/python
+# 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.
+
+"""Redirects to the version of dartfmt checked into a gclient repo.
+
+dartfmt binaries are pulled down during gclient sync in the mojo repo.
+
+This tool is named dart_format.py instead of dartfmt to parallel
+clang_format.py, which is in this same repository."""
+
+import os
+import subprocess
+import sys
+
+import gclient_utils
+
+class NotFoundError(Exception):
+  """A file could not be found."""
+  def __init__(self, e):
+    Exception.__init__(self,
+        'Problem while looking for dartfmt in Chromium source tree:\n'
+        '  %s' % e)
+
+
+def FindDartFmtToolInChromiumTree():
+  """Return a path to the dartfmt executable, or die trying."""
+  primary_solution_path = gclient_utils.GetPrimarySolutionPath()
+  if not primary_solution_path:
+    raise NotFoundError(
+        'Could not find checkout in any parent of the current path.')
+
+  dartfmt_path = os.path.join(primary_solution_path, 'third_party', 'dart-sdk',
+                              'dart-sdk', 'bin', 'dartfmt')
+  if not os.path.exists(dartfmt_path):
+    raise NotFoundError('File does not exist: %s' % dartfmt_path)
+  return dartfmt_path
+
+
+def main(args):
+  try:
+    tool = FindDartFmtToolInChromiumTree()
+  except NotFoundError, e:
+    print >> sys.stderr, e
+    sys.exit(1)
+
+  # Add some visibility to --help showing where the tool lives, since this
+  # redirection can be a little opaque.
+  help_syntax = ('-h', '--help', '-help', '-help-list', '--help-list')
+  if any(match in args for match in help_syntax):
+    print '\nDepot tools redirects you to the dartfmt at:\n    %s\n' % tool
+
+  return subprocess.call([tool] + sys.argv[1:])
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))
diff --git a/gclient_utils.py b/gclient_utils.py
index 96989a9..f80cd78 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -662,15 +662,8 @@
   raise Error('Unknown platform: ' + sys.platform)
 
 
-def GetBuildtoolsPath():
-  """Returns the full path to the buildtools directory.
-  This is based on the root of the checkout containing the current directory."""
-
-  # Overriding the build tools path by environment is highly unsupported and may
-  # break without warning.  Do not rely on this for anything important.
-  override = os.environ.get('CHROMIUM_BUILDTOOLS_PATH')
-  if override is not None:
-    return override
+def GetPrimarySolutionPath():
+  """Returns the full path to the primary solution. (gclient_root + src)"""
 
   gclient_root = FindGclientRoot(os.getcwd())
   if not gclient_root:
@@ -691,9 +684,24 @@
 
   # Some projects' top directory is not named 'src'.
   source_dir_name = GetGClientPrimarySolutionName(gclient_root) or 'src'
-  buildtools_path = os.path.join(gclient_root, source_dir_name, 'buildtools')
+  return os.path.join(gclient_root, source_dir_name)
+
+
+def GetBuildtoolsPath():
+  """Returns the full path to the buildtools directory.
+  This is based on the root of the checkout containing the current directory."""
+
+  # Overriding the build tools path by environment is highly unsupported and may
+  # break without warning.  Do not rely on this for anything important.
+  override = os.environ.get('CHROMIUM_BUILDTOOLS_PATH')
+  if override is not None:
+    return override
+
+  primary_solution = GetPrimarySolutionPath()
+  buildtools_path = os.path.join(primary_solution, 'buildtools')
   if not os.path.exists(buildtools_path):
     # Buildtools may be in the gclient root.
+    gclient_root = FindGclientRoot(os.getcwd())
     buildtools_path = os.path.join(gclient_root, 'buildtools')
   return buildtools_path
 
diff --git a/git_cl.py b/git_cl.py
index 1b375e8..728bae7 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -36,6 +36,7 @@
 from third_party import upload
 import breakpad  # pylint: disable=W0611
 import clang_format
+import dart_format
 import fix_encoding
 import gclient_utils
 import git_common
@@ -2894,6 +2895,26 @@
       disable_color=options.no_color).run()
 
 
+def BuildGitDiffCmd(diff_type, upstream_commit, args, extensions):
+  """Generates a diff command."""
+  # Generate diff for the current branch's changes.
+  diff_cmd = ['diff', '--no-ext-diff', '--no-prefix', diff_type,
+              upstream_commit, '--' ]
+
+  if args:
+    for arg in args:
+      if os.path.isdir(arg):
+        diff_cmd.extend(os.path.join(arg, '*' + ext) for ext in extensions)
+      elif os.path.isfile(arg):
+        diff_cmd.append(arg)
+      else:
+        DieWithError('Argument "%s" is not a file or a directory' % arg)
+  else:
+    diff_cmd.extend('*' + ext for ext in extensions)
+
+  return diff_cmd
+
+
 @subcommand.usage('[files or directories to diff]')
 def CMDformat(parser, args):
   """Runs clang-format on the diff."""
@@ -2912,15 +2933,6 @@
   if rel_base_path:
     os.chdir(rel_base_path)
 
-  # Generate diff for the current branch's changes.
-  diff_cmd = ['diff', '--no-ext-diff', '--no-prefix']
-  if opts.full:
-    # Only list the names of modified files.
-    diff_cmd.append('--name-only')
-  else:
-    # Only generate context-less patches.
-    diff_cmd.append('-U0')
-
   # Grab the merge-base commit, i.e. the upstream commit of the current
   # branch when it was created or the last time it was rebased. This is
   # to cover the case where the user may have called "git fetch origin",
@@ -2936,20 +2948,14 @@
     DieWithError('Could not find base commit for this branch. '
                  'Are you in detached state?')
 
-  diff_cmd.append(upstream_commit)
-
-  # Handle source file filtering.
-  diff_cmd.append('--')
-  if args:
-    for arg in args:
-      if os.path.isdir(arg):
-        diff_cmd += [os.path.join(arg, '*' + ext) for ext in CLANG_EXTS]
-      elif os.path.isfile(arg):
-        diff_cmd.append(arg)
-      else:
-        DieWithError('Argument "%s" is not a file or a directory' % arg)
+  if opts.full:
+    # Only list the names of modified files.
+    clang_diff_type = '--name-only'
   else:
-    diff_cmd += ['*' + ext for ext in CLANG_EXTS]
+    # Only generate context-less patches.
+    clang_diff_type = '-U0'
+
+  diff_cmd = BuildGitDiffCmd(clang_diff_type, upstream_commit, args, CLANG_EXTS)
   diff_output = RunGit(diff_cmd)
 
   top_dir = os.path.normpath(
@@ -2961,18 +2967,20 @@
   except clang_format.NotFoundError, e:
     DieWithError(e)
 
+  # Set to 2 to signal to CheckPatchFormatted() that this patch isn't
+  # formatted. This is used to block during the presubmit.
+  return_value = 0
+
   if opts.full:
     # diff_output is a list of files to send to clang-format.
     files = diff_output.splitlines()
-    if not files:
-      print "Nothing to format."
-      return 0
-    cmd = [clang_format_tool]
-    if not opts.dry_run and not opts.diff:
-      cmd.append('-i')
-    stdout = RunCommand(cmd + files, cwd=top_dir)
-    if opts.diff:
-      sys.stdout.write(stdout)
+    if files:
+      cmd = [clang_format_tool]
+      if not opts.dry_run and not opts.diff:
+        cmd.append('-i')
+      stdout = RunCommand(cmd + files, cwd=top_dir)
+      if opts.diff:
+        sys.stdout.write(stdout)
   else:
     env = os.environ.copy()
     env['PATH'] = str(os.path.dirname(clang_format_tool))
@@ -2991,9 +2999,29 @@
     if opts.diff:
       sys.stdout.write(stdout)
     if opts.dry_run and len(stdout) > 0:
-      return 2
+      return_value = 2
 
-  return 0
+  # Build a diff command that only operates on dart files. dart's formatter
+  # does not have the nice property of only operating on modified chunks, so
+  # hard code full.
+  dart_diff_cmd = BuildGitDiffCmd('--name-only', upstream_commit,
+                                  args, ['.dart'])
+  dart_diff_output = RunGit(dart_diff_cmd)
+  if dart_diff_output:
+    try:
+      command = [dart_format.FindDartFmtToolInChromiumTree()]
+      if not opts.dry_run and not opts.diff:
+        command.append('-w')
+      command.extend(dart_diff_output.splitlines())
+
+      stdout = RunCommand(command, cwd=top_dir, env=env)
+      if opts.dry_run and stdout:
+        return_value = 2
+    except dart_format.NotFoundError as e:
+      print ('Unable to check dart code formatting. Dart SDK is not in ' +
+             'this checkout.')
+
+  return return_value
 
 
 def CMDlol(parser, args):
diff --git a/presubmit_canned_checks.py b/presubmit_canned_checks.py
index 4e55d50..1e2d1ab 100644
--- a/presubmit_canned_checks.py
+++ b/presubmit_canned_checks.py
@@ -1097,7 +1097,7 @@
   code, _ = git_cl.RunGitWithCode(cmd, suppress_stderr=True)
   if code == 2:
     return [output_api.PresubmitPromptWarning(
-      'The %s directory requires clang-formatting. '
+      'The %s directory requires source formatting. '
       'Please run git cl format %s' %
       (input_api.basename(input_api.PresubmitLocalPath()),
        input_api.basename(input_api.PresubmitLocalPath())))]