This CL is based on the patch:

build/scan_sources.py

Index: build/scan_sources.py
===================================================================
--- build/scan_sources.py	(revision 108325)
+++ build/scan_sources.py	(working copy)
@@ -1,236 +0,0 @@
-#!/usr/bin/python
-# Copyright (c) 2011 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.
-
-from optparse import OptionParser
-import os
-import re
-import sys
-
-"""Header Scanner.
-
-This module will scan a set of input sources for include dependencies.  Use
-the command-line switch -Ixxxx to add include paths.  All filenames and paths
-are expected and returned with POSIX separators.
-"""
-
-
-debug = False
-
-
-def DebugPrint(txt):
-  if debug: print txt
-
-
-class PathConverter(object):
-  """PathConverter does path manipulates using Posix style pathnames.
-
-  Regardless of the native path type, all inputs and outputs to the path
-  functions are with POSIX style separators.
-  """
-  def ToNativePath(self, pathname):
-    return os.path.sep.join(pathname.split('/'))
-
-  def ToPosixPath(self, pathname):
-    return '/'.join(pathname.split(os.path.sep))
-
-  def exists(self, pathname):
-    ospath = self.ToNativePath(pathname)
-    return os.path.exists(ospath)
-
-  def getcwd(self):
-    return self.ToPosixPath(os.getcwd())
-
-  def isabs(self, pathname):
-    ospath = self.ToNativePath(pathname)
-    return os.path.isabs(ospath)
-
-  def isdir(self, pathname):
-    ospath = self.ToNativePath(pathname)
-    return os.path.isdir(ospath)
-
-  def open(self, pathname):
-    ospath = self.ToNativePath(pathname)
-    return open(ospath)
-
-  def realpath(self, pathname):
-    ospath = self.ToNativePath(pathname)
-    ospath = os.path.realpath(ospath)
-    return self.ToPosixPath(ospath)
-
-
-class Resolver(object):
-  """Resolver finds and generates relative paths for include files.
-
-  The Resolver object provides a mechanism to to find and convert a source or
-  include filename into a relative path based on provided search paths.  All
-  paths use POSIX style separator.
-  """
-  def __init__(self, pathobj=PathConverter()):
-    self.search_dirs = []
-    self.pathobj = pathobj
-    self.cwd = self.pathobj.getcwd()
-    self.offs = len(self.cwd)
-
-  def AddOneDirectory(self, pathname):
-    """Add an include search path."""
-    pathname = self.pathobj.realpath(pathname)
-    DebugPrint('Adding DIR: %s' % pathname)
-    if pathname not in self.search_dirs:
-      if self.pathobj.isdir(pathname):
-        self.search_dirs.append(pathname)
-      else:
-        sys.stderr.write('Not a directory: %s\n' % pathname)
-        return False
-    return True
-
-  def AddDirectories(self, pathlist):
-    """Add list of space separated directories."""
-    failed = False
-    dirlist = ' '.join(pathlist)
-    for dirname in dirlist.split(' '):
-      if not self.AddOneDirectory(dirname):
-        failed = True
-    return not failed
-
-  def GetDirectories(self):
-    return self.search_dirs
-
-  def RealToRelative(self, filepath, basepath):
-    """Returns a relative path from an absolute basepath and filepath."""
-    path_parts = filepath.split('/')
-    base_parts = basepath.split('/')
-    while path_parts and base_parts and path_parts[0] == base_parts[0]:
-      path_parts = path_parts[1:]
-      base_parts = base_parts[1:]
-    rel_parts = ['..'] * len(base_parts) + path_parts
-    return '/'.join(rel_parts)
-
-  def FilenameToRelative(self, filepath):
-    """Returns a relative path from CWD to filepath."""
-    filepath = self.pathobj.realpath(filepath)
-    basepath = self.cwd
-    return self.RealToRelative(filepath, basepath)
-
-  def FindFile(self, filename):
-    """Search for <filename> across the search directories, if the path is not
-       absolute.  Return the filepath relative to the CWD or None. """
-    if self.pathobj.isabs(filename):
-      if self.pathobj.exists(filename):
-        return self.FilenameToRelative(filename)
-      return None
-    for pathname in self.search_dirs:
-      fullname = '%s/%s' % (pathname, filename)
-      if self.pathobj.exists(fullname):
-        return self.FilenameToRelative(fullname)
-    return None
-
-
-def LoadFile(filename):
-  # Catch cases where the file does not exist
-  try:
-    fd = PathConverter().open(filename)
-  except IOError:
-    DebugPrint('Exception on file: %s' % filename)
-    return ''
-  # Go ahead and throw if you fail to read
-  return fd.read()
-
-
-class Scanner(object):
-  """Scanner searches for '#include' to find dependencies."""
-
-  def __init__(self, loader=None):
-    regex = r'\#[ \t]*include[ \t]*[<"]([^>^"]+)[>"]'
-    self.parser = re.compile(regex)
-    self.loader = loader
-    if not loader:
-      self.loader = LoadFile
-
-  def ScanData(self, data):
-    """Generate a list of includes from this text block."""
-    return self.parser.findall(data)
-
-  def ScanFile(self, filename):
-    """Generate a list of includes from this filename."""
-    includes = self.ScanData(self.loader(filename))
-    DebugPrint('Source %s contains:\n\t%s' % (filename, '\n\t'.join(includes)))
-    return includes
-
-
-class WorkQueue(object):
-  """WorkQueue contains the list of files to be scanned.
-
-  WorkQueue contains provides a queue of files to be processed.  The scanner
-  will attempt to push new items into the queue, which will be ignored if the
-  item is already in the queue.  If the item is new, it will be added to the
-  work list, which is drained by the scanner.
-  """
-  def __init__(self, resolver, scanner=Scanner()):
-    self.added_set = set()
-    self.todo_list = list()
-    self.scanner = scanner
-    self.resolver = resolver
-
-  def PushIfNew(self, filename):
-    """Add this dependency to the list of not already there."""
-    DebugPrint('Adding %s' % filename)
-    resolved_name = self.resolver.FindFile(filename)
-    if not resolved_name:
-      DebugPrint('Failed to resolve %s' % filename)
-      return
-    DebugPrint('Resolvd as %s' % resolved_name)
-    if resolved_name in self.added_set:
-      return
-    self.todo_list.append(resolved_name)
-    self.added_set.add(resolved_name)
-
-  def PopIfAvail(self):
-    """Fetch the next dependency to search."""
-    if not self.todo_list:
-      return None
-    return self.todo_list.pop()
-
-  def Run(self):
-    """Search through the available dependencies until the list becomes empty.
-      The list must be primed with one or more source files to search."""
-    scan_name = self.PopIfAvail()
-    while scan_name:
-      includes = self.scanner.ScanFile(scan_name)
-      for include_file in includes:
-        self.PushIfNew(include_file)
-      scan_name = self.PopIfAvail()
-    return sorted(self.added_set)
-
-
-def Main(argv):
-  global debug
-  parser = OptionParser()
-  parser.add_option('-I', dest='includes', action='append',
-                    help='Set include path.')
-  parser.add_option('-D', dest='debug', action='store_true',
-                    help='Enable debugging output.', default=False)
-  (options, files) = parser.parse_args(argv[1:])
-
-  if options.debug:
-    debug = Trueglobal_var_name,
-
-  resolver = Resolver()
-  if options.includes:
-    if not resolver.AddDirectories(options.includes):
-      return -1
-
-  workQ = WorkQueue(resolver)
-  for filename in files:
-    workQ.PushIfNew(filename)
-
-  sorted_list = workQ.Run()
-  for pathname in sorted_list:
-    sys.stderr.write(pathname + '\n')
-  return 0
-
-
-if __name__ == '__main__':
-  sys.exit(Main(sys.argv))
-