Add the device_status dimension to all triggered CrOS device tests.

This will ensure the tests only run on bots with healthy devices. Note
that we're not using a bot's quarantining method to do so since we also
want tasks that can heal an unhealthy device to still run.

Bug: 866062
Change-Id: Ieac1b8f5e58c2c49813952d039337dbfba20373c
Reviewed-on: https://chromium-review.googlesource.com/c/1474287
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632906}

diff --git a/testing/test.gni b/testing/test.gni
index a7dd581..eac0fdd 100644
--- a/testing/test.gni
+++ b/testing/test.gni

@@ -353,6 +353,9 @@
         data = []
       }
 
+      # We use a special trigger script for CrOS hardware tests.
+      data += [ "//testing/trigger_scripts/chromeos_device_trigger.py" ]
+
       testonly = true
       output_name = target_name
       write_runtime_deps = _runtime_deps_file

diff --git a/testing/trigger_scripts/chromeos_device_trigger.py b/testing/trigger_scripts/chromeos_device_trigger.py
index 61ce229..7ac28fa2 100755
--- a/testing/trigger_scripts/chromeos_device_trigger.py
+++ b/testing/trigger_scripts/chromeos_device_trigger.py

@@ -101,8 +101,17 @@
   # Insert our modified dimension args in between the 1st and 2nd args of the
   # initial `swarming.py` invocation. This avoids the presence of the special
   # `--` arg from causing swarming.py to ignore them.
+  needs_device_status = True
   for k, v in args.dimensions:
     new_args.extend(['--dimension', k, v])
+    if k == 'device_status':
+      needs_device_status = False
+
+  # Only CrOS device bots with a device_status dimension of "available" should
+  # run tests. So target those explicitly if we aren't already.
+  if needs_device_status:
+    new_args.extend(['--dimension', 'device_status', 'available'])
+
   new_args.extend([
       '--optional-dimension',
       'device_os',