diff --git a/bin/closure/depswriter.py b/bin/closure/depswriter.py
new file mode 100644
index 0000000000..dfecc4bf74
--- /dev/null
+++ b/bin/closure/depswriter.py
@@ -0,0 +1,202 @@
+#!/usr/bin/env python
+#
+# Copyright 2009 The Closure Library Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS-IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""Generates out a Closure deps.js file given a list of JavaScript sources.
+
+Paths can be specified as arguments or (more commonly) specifying trees
+with the flags (call with --help for descriptions).
+
+Usage: depswriter.py [path/to/js1.js [path/to/js2.js] ...]
+"""
+
+import logging
+import optparse
+import os
+import posixpath
+import shlex
+import sys
+
+import source
+import treescan
+
+
+__author__ = 'nnaze@google.com (Nathan Naze)'
+
+
+def MakeDepsFile(source_map):
+  """Make a generated deps file.
+
+  Args:
+    source_map: A dict map of the source path to source.Source object.
+
+  Returns:
+    str, A generated deps file source.
+  """
+
+  # Write in path alphabetical order
+  paths = sorted(source_map.keys())
+
+  lines = []
+
+  for path in paths:
+    js_source = source_map[path]
+
+    # We don't need to add entries that don't provide anything.
+    if js_source.provides:
+      lines.append(_GetDepsLine(path, js_source))
+
+  return ''.join(lines)
+
+
+def _GetDepsLine(path, js_source):
+  """Get a deps.js file string for a source."""
+
+  provides = sorted(js_source.provides)
+  requires = sorted(js_source.requires)
+
+  return 'goog.addDependency(\'%s\', %s, %s);\n' % (path, provides, requires)
+
+
+def _GetOptionsParser():
+  """Get the options parser."""
+
+  parser = optparse.OptionParser(__doc__)
+
+  parser.add_option('--output_file',
+                    dest='output_file',
+                    action='store',
+                    help=('If specified, write output to this path instead of '
+                          'writing to standard output.'))
+  parser.add_option('--root',
+                    dest='roots',
+                    default=[],
+                    action='append',
+                    help='A root directory to scan for JS source files. '
+                    'Paths of JS files in generated deps file will be '
+                    'relative to this path.  This flag may be specified '
+                    'multiple times.')
+  parser.add_option('--root_with_prefix',
+                    dest='roots_with_prefix',
+                    default=[],
+                    action='append',
+                    help='A root directory to scan for JS source files, plus '
+                    'a prefix (if either contains a space, surround with '
+                    'quotes).  Paths in generated deps file will be relative '
+                    'to the root, but preceded by the prefix.  This flag '
+                    'may be specified multiple times.')
+  parser.add_option('--path_with_depspath',
+                    dest='paths_with_depspath',
+                    default=[],
+                    action='append',
+                    help='A path to a source file and an alternate path to '
+                    'the file in the generated deps file (if either contains '
+                    'a space, surround with whitespace). This flag may be '
+                    'specified multiple times.')
+  return parser
+
+
+def _NormalizePathSeparators(path):
+  """Replaces OS-specific path separators with POSIX-style slashes.
+
+  Args:
+    path: str, A file path.
+
+  Returns:
+    str, The path with any OS-specific path separators (such as backslash on
+      Windows) replaced with URL-compatible forward slashes. A no-op on systems
+      that use POSIX paths.
+  """
+  return path.replace(os.sep, posixpath.sep)
+
+
+def _GetRelativePathToSourceDict(root, prefix=''):
+  """Scans a top root directory for .js sources.
+
+  Args:
+    root: str, Root directory.
+    prefix: str, Prefix for returned paths.
+
+  Returns:
+    dict, A map of relative paths (with prefix, if given), to source.Source
+      objects.
+  """
+  # Remember and restore the cwd when we're done. We work from the root so
+  # that paths are relative from the root.
+  start_wd = os.getcwd()
+  os.chdir(root)
+
+  path_to_source = {}
+  for path in treescan.ScanTreeForJsFiles('.'):
+    prefixed_path = _NormalizePathSeparators(os.path.join(prefix, path))
+    path_to_source[prefixed_path] = source.Source(source.GetFileContents(path))
+
+  os.chdir(start_wd)
+
+  return path_to_source
+
+
+def _GetPair(s):
+  """Return a string as a shell-parsed tuple.  Two values expected."""
+  try:
+    # shlex uses '\' as an escape character, so they must be escaped.
+    s = s.replace('\\', '\\\\')
+    first, second = shlex.split(s)
+    return (first, second)
+  except:
+    raise Exception('Unable to parse input line as a pair: %s' % s)
+
+
+def main():
+  """CLI frontend to MakeDepsFile."""
+  logging.basicConfig(format=(sys.argv[0] + ': %(message)s'),
+                      level=logging.INFO)
+  options, args = _GetOptionsParser().parse_args()
+
+  path_to_source = {}
+
+  # Roots without prefixes
+  for root in options.roots:
+    path_to_source.update(_GetRelativePathToSourceDict(root))
+
+  # Roots with prefixes
+  for root_and_prefix in options.roots_with_prefix:
+    root, prefix = _GetPair(root_and_prefix)
+    path_to_source.update(_GetRelativePathToSourceDict(root, prefix=prefix))
+
+  # Source paths
+  for path in args:
+    path_to_source[path] = source.Source(source.GetFileContents(path))
+
+  # Source paths with alternate deps paths
+  for path_with_depspath in options.paths_with_depspath:
+    srcpath, depspath = _GetPair(path_with_depspath)
+    path_to_source[depspath] = source.Source(source.GetFileContents(srcpath))
+
+  # Make our output pipe.
+  if options.output_file:
+    out = open(options.output_file, 'w')
+  else:
+    out = sys.stdout
+
+  out.write('// This file was autogenerated by %s.\n' % sys.argv[0])
+  out.write('// Please do not edit.\n')
+
+  out.write(MakeDepsFile(path_to_source))
+
+
+if __name__ == '__main__':
+  main()
diff --git a/bin/closure/source.py b/bin/closure/source.py
new file mode 100644
index 0000000000..c2ee1fbb26
--- /dev/null
+++ b/bin/closure/source.py
@@ -0,0 +1,114 @@
+# Copyright 2009 The Closure Library Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS-IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""Scans a source JS file for its provided and required namespaces.
+
+Simple class to scan a JavaScript file and express its dependencies.
+"""
+
+__author__ = 'nnaze@google.com'
+
+
+import re
+
+_BASE_REGEX_STRING = '^\s*goog\.%s\(\s*[\'"](.+)[\'"]\s*\)'
+_PROVIDE_REGEX = re.compile(_BASE_REGEX_STRING % 'provide')
+_REQUIRES_REGEX = re.compile(_BASE_REGEX_STRING % 'require')
+
+# This line identifies base.js and should match the line in that file.
+_GOOG_BASE_LINE = (
+    'var goog = goog || {}; // Identifies this file as the Closure base.')
+
+
+class Source(object):
+  """Scans a JavaScript source for its provided and required namespaces."""
+
+  # Matches a "/* ... */" comment.
+  # Note: We can't definitively distinguish a "/*" in a string literal without a
+  # state machine tokenizer. We'll assume that a line starting with whitespace
+  # and "/*" is a comment.
+  _COMMENT_REGEX = re.compile(
+      r"""
+      ^\s*   # Start of a new line and whitespace
+      /\*    # Opening "/*"
+      .*?    # Non greedy match of any characters (including newlines)
+      \*/    # Closing "*/""",
+      re.MULTILINE | re.DOTALL | re.VERBOSE)
+
+  def __init__(self, source):
+    """Initialize a source.
+
+    Args:
+      source: str, The JavaScript source.
+    """
+
+    self.provides = set()
+    self.requires = set()
+
+    self._source = source
+    self._ScanSource()
+
+  def __str__(self):
+    return 'Source %s' % self._path
+
+  def GetSource(self):
+    """Get the source as a string."""
+    return self._source
+
+  @classmethod
+  def _StripComments(cls, source):
+    return cls._COMMENT_REGEX.sub('', source)
+
+  def _ScanSource(self):
+    """Fill in provides and requires by scanning the source."""
+
+    source = self._StripComments(self.GetSource())
+
+    source_lines = source.splitlines()
+    for line in source_lines:
+      match = _PROVIDE_REGEX.match(line)
+      if match:
+        self.provides.add(match.group(1))
+      match = _REQUIRES_REGEX.match(line)
+      if match:
+        self.requires.add(match.group(1))
+
+    # Closure's base file implicitly provides 'goog'.
+    for line in source_lines:
+      if line == _GOOG_BASE_LINE:
+        if len(self.provides) or len(self.requires):
+          raise Exception(
+              'Base files should not provide or require namespaces.')
+        self.provides.add('goog')
+
+
+def GetFileContents(path):
+  """Get a file's contents as a string.
+
+  Args:
+    path: str, Path to file.
+
+  Returns:
+    str, Contents of file.
+
+  Raises:
+    IOError: An error occurred opening or reading the file.
+
+  """
+  fileobj = open(path)
+  try:
+    return fileobj.read()
+  finally:
+    fileobj.close()
diff --git a/bin/closure/treescan.py b/bin/closure/treescan.py
new file mode 100644
index 0000000000..6694593aab
--- /dev/null
+++ b/bin/closure/treescan.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python
+#
+# Copyright 2010 The Closure Library Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS-IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""Shared utility functions for scanning directory trees."""
+
+import os
+import re
+
+
+__author__ = 'nnaze@google.com (Nathan Naze)'
+
+
+# Matches a .js file path.
+_JS_FILE_REGEX = re.compile(r'^.+\.js$')
+
+
+def ScanTreeForJsFiles(root):
+  """Scans a directory tree for JavaScript files.
+
+  Args:
+    root: str, Path to a root directory.
+
+  Returns:
+    An iterable of paths to JS files, relative to cwd.
+  """
+  return ScanTree(root, path_filter=_JS_FILE_REGEX)
+
+
+def ScanTree(root, path_filter=None, ignore_hidden=True):
+  """Scans a directory tree for files.
+
+  Args:
+    root: str, Path to a root directory.
+    path_filter: A regular expression filter.  If set, only paths matching
+      the path_filter are returned.
+    ignore_hidden: If True, do not follow or return hidden directories or files
+      (those starting with a '.' character).
+
+  Yields:
+    A string path to files, relative to cwd.
+  """
+
+  def OnError(os_error):
+    raise os_error
+
+  for dirpath, dirnames, filenames in os.walk(root, onerror=OnError):
+    # os.walk allows us to modify dirnames to prevent decent into particular
+    # directories.  Avoid hidden directories.
+    for dirname in dirnames:
+      if ignore_hidden and dirname.startswith('.'):
+        dirnames.remove(dirname)
+
+    for filename in filenames:
+
+      # nothing that starts with '.'
+      if ignore_hidden and filename.startswith('.'):
+        continue
+
+      fullpath = os.path.join(dirpath, filename)
+
+      if path_filter and not path_filter.match(fullpath):
+        continue
+
+      yield os.path.normpath(fullpath)