Adding latency_unittests to run on trybots.

testing/buildbot/chromium.chromiumos.json

Index: testing/buildbot/chromium.chromiumos.json
diff --git a/testing/buildbot/chromium.chromiumos.json b/testing/buildbot/chromium.chromiumos.json
index dcef2a67c33e84be5eeef1b7ae4222aa7f66d06f..ec441bfc202c07f7ab272f6a55bead621a9b68ff 100644
--- a/testing/buildbot/chromium.chromiumos.json
+++ b/testing/buildbot/chromium.chromiumos.json
@@ -228,6 +228,12 @@
         "test": "jingle_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "latency_unittests"
+      },
+      {
         "args": [
           "--ozone-platform=headless",
           "--override-use-software-gl-for-tests",
@@ -668,6 +674,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "latency_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "media_blink_unittests"
       },
       {
@@ -1020,6 +1032,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "latency_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "media_blink_unittests"
       },
       {