Enables ASAN build and test for Dart

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of 'src').
 #
@@ skipping 19 matching lines @@
   # the commit queue can handle CLs rolling ANGLE
   # and whatever else without interference from each other.
   'angle_revision': '73edef0a2a162e943d5be7715f53bee5d9452b2e',
   # 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': '5c5e924788fe40f7d6e0a3841ac572de2475e689',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Dart
   # and whatever else without interference from each other.
-  'dart_revision': '43719',
+  'dart_revision': '43955',
   # 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': '58985096a7852263df68e87d9bfc335a3e2759bf',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.
   'boringssl_revision': 'd306f165a462f47c2c0e8f3a0f2b4ae6950f70ed',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling lss
@@ skipping 281 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]