android-rel builder was failing due to DEX limit

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/android-rel/5323

FAILED: gen/chrome/android/chrome_public_bundle/chrome_public_bundle__unsplit_dex.zip 
python ../../build/android/gyp/dex.py --depfile gen/chrome/android/chrome_public_bundle__unsplit_dex.d --dex-path gen/chrome/android/chrome_public_bundle/chrome_public_bundle__unsplit_dex.zip gen/chrome/android/chrome_public_bundle/chrome_public_bundle__unsplit_dex.zip.proguard.jar --release --d8-jar-path ../../third_party/r8/lib/d8.jar
Traceback (most recent call last):
  File "../../build/android/gyp/dex.py", line 347, in <module>
    sys.exit(main(sys.argv[1:]))
  File "../../build/android/gyp/dex.py", line 319, in main
    _RunD8(dex_cmd, paths, tmp_dex_dir)
  File "../../build/android/gyp/dex.py", line 152, in _RunD8
    build_utils.CheckOutput(dex_cmd, print_stderr=False)
  File "/b/swarming/w/ir/cache/builder/src/build/android/gyp/util/build_utils.py", line 218, in CheckOutput
    raise CalledProcessError(cwd, args, stdout + stderr)
util.build_utils.CalledProcessError: Command failed: ( cd /b/swarming/w/ir/cache/builder/src/out/Release; java -jar ../../third_party/r8/lib/d8.jar --no-desugaring --release --output /b/swarming/w/ir/tmp/t/tmp0I2e3N gen/chrome/android/chrome_public_bundle/chrome_public_bundle__unsplit_dex.zip.proguard.jar )
Error: Cannot fit requested classes in a single dex file (# methods: 65561 > 65536). Try supplying a main-dex list
Compilation failed

I'm unfamiliar with what chrome_public_bundle is and what our options going forward are. This is likely going to start blocking everyone from checking in patches that add to the Java method count.