[Config] Add service accounts for the example builder

Bug:1300370
Change-Id: Ie8a3260c8539ea1aea736cc0f4bb4bfd61ac5871
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3622237
Reviewed-by: Dennis Kempin <denniskempin@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Yuanjun Huang <yuanjunh@google.com>
diff --git a/infra/config/generated/cr-buildbucket.cfg b/infra/config/generated/cr-buildbucket.cfg
index d4d54aa..6755649 100644
--- a/infra/config/generated/cr-buildbucket.cfg
+++ b/infra/config/generated/cr-buildbucket.cfg
@@ -26,6 +26,7 @@
         '{'
         '  "recipe": "hello_world"'
         '}'
+      service_account: "crosvm-luci-ci-builder@crosvm-infra.iam.gserviceaccount.com"
       experiments {
         key: "luci.recipes.use_python3"
         value: 100
diff --git a/infra/config/generated/realms.cfg b/infra/config/generated/realms.cfg
index 2cf7abd..6222112 100644
--- a/infra/config/generated/realms.cfg
+++ b/infra/config/generated/realms.cfg
@@ -58,6 +58,10 @@
 realms {
   name: "ci"
   bindings {
+    role: "role/buildbucket.builderServiceAccount"
+    principals: "user:crosvm-luci-ci-builder@crosvm-infra.iam.gserviceaccount.com"
+  }
+  bindings {
     role: "role/buildbucket.triggerer"
     principals: "group:mdb/crosvm-acl-luci-admin"
   }
diff --git a/infra/config/main.star b/infra/config/main.star
index b29e239..152bd65 100755
--- a/infra/config/main.star
+++ b/infra/config/main.star
@@ -122,4 +122,5 @@
         name = "hello_world",
     ),
     schedule = "with 1m interval",
+    service_account = "crosvm-luci-ci-builder@crosvm-infra.iam.gserviceaccount.com",
 )