Enable pre-test flashing for base_unittests on internal CrOS HW testers.

This tests it out on a single test suite. If it looks good, it'll be
rolled out more broadly.

This will let us tear-down all the out-of-band flashing logic for
these devices, and replace it with on-demand pre-test flashing. The
latter being much simpler to maintain, having less moving parts, and
generally being more visible.

Bug: 1057152
Change-Id: Ic2fba3725b01bec2d3dedc4898e8acfe3ad5b22d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2261702
Reviewed-by: Erik Chen <[email protected]>
Commit-Queue: Ben Pastene <[email protected]>
Cr-Commit-Position: refs/heads/master@{#781967}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 9669a9d2..3a7c9226 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -90,6 +90,21 @@
       'Linux FYI GPU TSAN Release',
     ],
   },
+  'base_unittests': {
+    'modifications': {
+      # TODO(crbug.com/1057152): Turn on flashing for all CrOS device tests.
+      'chromeos-eve-chrome': {
+        'args': [
+          '--flash',
+        ],
+      },
+      'chromeos-kevin-chrome': {
+        'args': [
+          '--flash',
+        ],
+      },
+    },
+  },
   'blink_web_tests': {
     'remove_from': [
       'Win 7 Tests x64 (1)',  # 64-bit win is unsupported by the layout tests.