Manually change DEPS URL for src/tools/swarming_client to match Chromium
Similar to https://chromium.googlesource.com/external/webrtc/+/4ccd9c1493979bb1b4721ffdfdc59568ce5a40db%5E%21/#F0

Also add downloading of third_party/bazel/desugar since it's not required
by the build toolchain on Android.

Change log: https://chromium.googlesource.com/chromium/src/+log/da6245e7c4..21e78fbe27
Full diff: https://chromium.googlesource.com/chromium/src/+/da6245e7c4..21e78fbe27

Changed dependencies:
* src/base: https://chromium.googlesource.com/chromium/src/base/+log/8c06e7a9f6..bdaf4d9893
* src/build: https://chromium.googlesource.com/chromium/src/build/+log/5a3f439e92..92ccaf1432
* src/buildtools: https://chromium.googlesource.com/chromium/buildtools.git/+log/5ad14542a6..cbc33b9c0a
* src/ios: https://chromium.googlesource.com/chromium/src/ios/+log/e5a58b0b43..436ef979f7
* src/testing: https://chromium.googlesource.com/chromium/src/testing/+log/ebf1c4622e..dcfc1809e9
* src/third_party: https://chromium.googlesource.com/chromium/src/third_party/+log/d58cf433a5..36421e57a8
* src/third_party/android_tools: https://chromium.googlesource.com/android_tools.git/+log/e9d4018e14..aadb2fed04
* src/third_party/catapult: https://chromium.googlesource.com/external/github.com/catapult-project/catapult.git/+log/9629af7533..c9667ecd29
* src/third_party/googletest/src: https://chromium.googlesource.com/external/github.com/google/googletest.git/+log/42bc671f47..7f8fefabed
* src/third_party/icu: https://chromium.googlesource.com/chromium/deps/icu.git/+log/1fec0c83e9..08cb956852
* src/third_party/robolectric/robolectric: https://chromium.googlesource.com/external/robolectric.git/+log/2a0b6ba221..b02c65cc6d
* src/third_party/yasm/source/patched-yasm: https://chromium.googlesource.com/chromium/deps/yasm/patched-yasm.git/+log/7da28c6c7c..b98114e18d
* src/tools: https://chromium.googlesource.com/chromium/src/tools/+log/f79809d034..5d14bcccf1
* src/tools/swarming_client: https://chromium.googlesource.com/infra/luci/client-py.git/+log/a56c2b39ca..72b6a2dc60
DEPS diff: https://chromium.googlesource.com/chromium/src/+/da6245e7c4..21e78fbe27/DEPS

Clang version changed 308728:310694
Details: https://chromium.googlesource.com/chromium/src/+/da6245e7c4..21e78fbe27/tools/clang/scripts/update.py

TBR=fbarchard@google.com
BUG=None
NOTRY=True

Change-Id: Ic0fdefb7def1407e69e74d2c87e4316c323b383b
Reviewed-on: https://chromium-review.googlesource.com/654639
Commit-Queue: Henrik Kjellander <kjellander@chromium.org>
Reviewed-by: Henrik Kjellander <kjellander@chromium.org>