[tools] Remove tools/presubmit.py and move unittests/PRESUBMIT.py into its place

R=machenbach@chromium.org

No-Try: true
Bug: chromium:899028
Change-Id: I1de1f393989a63d165209e78f19284053c73ba08
Reviewed-on: https://chromium-review.googlesource.com/c/1307423
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57147}

tools/unittests/PRESUBMIT.py → tools/PRESUBMIT.py

@@ -3,8 +3,6 @@
 # found in the LICENSE file.
 
 def CheckChangeOnCommit(input_api, output_api):
-  # TODO(machenbach): Run all unittests.
   tests = input_api.canned_checks.GetUnitTestsInDirectory(
-      input_api, output_api, '.',
-      whitelist=['run_tests_test.py$', 'run_perf_test.py$'])
+      input_api, output_api, 'unittests')
   return input_api.RunTests(tests)