Create a mechanism define declarative rules via the extension manifest.

extensions/test/data/manifest_tests/event_rules.json

Index: extensions/test/data/manifest_tests/event_rules.json
diff --git a/extensions/test/data/manifest_tests/event_rules.json b/extensions/test/data/manifest_tests/event_rules.json
new file mode 100644
index 0000000000000000000000000000000000000000..649587447c651e29e66f564f8694dec3997499c1
--- /dev/null
+++ b/extensions/test/data/manifest_tests/event_rules.json
@@ -0,0 +1,15 @@
+{
+  "name": "extensions_unittests --gtest_filter=DeclarativeManifestTest.Valid",
+  "version": "1",
+  "manifest_version": 2,
+  "app": {
+    "background": {
+      "scripts": ["background.js"]
+    }
+  },
+  "event_rules": [{
+    "event": "foo",
+    "conditions": [{"type": "condition_type"}],
+    "actions": [{"type": "action_type"}]
+  }]
+}