Roll src/third_party/depot_tools a30b7bd35b10..30d08dd0e3c1 (2 commits)

https://chromium.googlesource.com/chromium/tools/depot_tools.git/+log/a30b7bd35b10..30d08dd0e3c1

git log a30b7bd35b10..30d08dd0e3c1 --date=short --first-parent --format='%ad %ae %s'
2020-03-18 sque@google.com Roll out new goma client binary VERSION=195
2020-03-18 huangs@chromium.org [Presubmit] Allow GetUnitTestsRecursively() to restrict Python versions.

Created with:
  gclient setdep -r src/third_party/depot_tools@30d08dd0e3c1

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/depot-tools-chromium-autoroll
Please CC agable@chromium.org on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: agable@chromium.org
Change-Id: I9bec5513ced650decb6cf4d3c7b0a4890297791e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108076Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#751310}

DEPS

@@ -877,7 +877,7 @@ deps = {
   },
 
   'src/third_party/depot_tools':
-    Var('chromium_git') + '/chromium/tools/depot_tools.git' + '@' + 'a30b7bd35b108a9dce12c4a6d2df773bb983988a',
+    Var('chromium_git') + '/chromium/tools/depot_tools.git' + '@' + '30d08dd0e3c12d658c149dc3144f315c9f00b401',
 
   'src/third_party/devtools-frontend/src':
     Var('chromium_git') + '/devtools/devtools-frontend' + '@' + Var('devtools_frontend_revision'),