Adding desugar as a dependency on android

DEPS

 # This file contains dependencies for WebRTC.
 
 vars = {
   'chromium_git': 'https://chromium.googlesource.com',
   'chromium_revision': '8fdcb934eebce9cc880e3d4b99b66951e2232499',
   'boringssl_git': 'https://boringssl.googlesource.com',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling swarming_client
   # and whatever else without interference from each other.
   'swarming_revision': '42721e128da760b345ab60d7cf34e300269112d7',
@@ skipping 512 matching lines @@
     'action': ['download_from_google_storage',
                '--directory',
                '--recursive',
                '--num_threads=10',
                '--no_auth',
                '--quiet',
                '--bucket', 'chromium-webrtc-resources',
                'src/resources'],
   },
 ]
+hooks_os = {
+  'android': [
+    {
+      'name': 'desugar',
+      'pattern': '.',
+      'action': ['python',
+                 'src/build/android/update_deps/update_third_party_deps.py',
+                 'download',
+                 '-b', 'chromium-android-tools/bazel/desugar',
+                 '-l', 'third_party/bazel/desugar'
+      ],
+    },
+  ],
+}
 recursedeps = [
   # buildtools provides clang_format, libc++, and libc++abi.
   'src/buildtools',
   # android_tools manages the NDK.
   'src/third_party/android_tools',
 ]