Convert unit_tests to run exclusively on Swarming

testing/buildbot/chromium.fyi.json

Index: testing/buildbot/chromium.fyi.json
diff --git a/testing/buildbot/chromium.fyi.json b/testing/buildbot/chromium.fyi.json
index 35b56009130e79f4ea609ee66bfd5954ea1e5884..1b46e2be4942ec815e79a64dab4cd46b39585490 100644
--- a/testing/buildbot/chromium.fyi.json
+++ b/testing/buildbot/chromium.fyi.json
@@ -1748,6 +1748,9 @@
         "test": "ui_base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "unit_tests"
       },
       {
@@ -1890,6 +1893,9 @@
         "test": "ui_base_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "unit_tests"
       },
       {
@@ -3006,6 +3012,9 @@
         "test": "ui_touch_selection_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "unit_tests"
       },
       {
@@ -3411,6 +3420,9 @@
         "test": "ui_touch_selection_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "unit_tests"
       },
       {