Mark ui_base_unittests target to be used on Swarming.

testing/buildbot/chromium.memory.json

Index: testing/buildbot/chromium.memory.json
diff --git a/testing/buildbot/chromium.memory.json b/testing/buildbot/chromium.memory.json
index c8ca1071635bd912a0ac1212afbbb2eed3cec6b7..a3706ecb6fadf84a71532370705c4fbea7713a4c 100644
--- a/testing/buildbot/chromium.memory.json
+++ b/testing/buildbot/chromium.memory.json
@@ -118,6 +118,9 @@
         "test": "sync_unit_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_base_unittests"
       },
       {
@@ -296,6 +299,9 @@
         "test": "sync_unit_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_base_unittests"
       },
       {
@@ -415,6 +421,9 @@
         "test": "sync_unit_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_base_unittests"
       },
       {
@@ -516,6 +525,9 @@
         "test": "sync_unit_tests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_base_unittests"
       },
       {