Add storage_unittests to buildbots.

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 02fd4079b9362bd80f95a7c9f2b939ffac0d3e88..18cc348f1d4bd9d2745b1ccb5aefb3b82c826347 100644
--- a/testing/buildbot/chromium.chromiumos.json
+++ b/testing/buildbot/chromium.chromiumos.json
@@ -322,6 +322,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "storage_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_arc_unittests"
       },
       {
@@ -700,6 +706,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "storage_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_arc_unittests"
       },
       {
@@ -1046,6 +1058,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "storage_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "ui_arc_unittests"
       },
       {