Roll buildtools forward by one revision.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 37 matching lines @@
   # the commit queue can handle CLs rolling swarming_client
   # and whatever else without interference from each other.
   'swarming_revision': '0b908f18767c8304dc089454bc1c91755d21f1f5',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling ANGLE
   # and whatever else without interference from each other.
   'angle_revision': '5b74bd390334b1c988bb4b941e7765b992f611f7',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling build tools
   # and whatever else without interference from each other.
-  'buildtools_revision': '11961c21510b90aa6057064459a1af53f3fff449',
+  'buildtools_revision': 'be55b9ad86a4a5f760895984f93f76038e08e29e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
   'pdfium_revision': '05e67415684adc36af228ca2f1e0efc30a40d242',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling openmax_dl
   # and whatever else without interference from each other.
   'openmax_dl_revision': '6670e52d32351145a6b6c198dab3f6a536edf3db',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
@@ skipping 744 matching lines @@
         'src/tools',
     ],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     'pattern': '.',
     'action': ['python', 'src/build/gyp_chromium'],
   },
 ]