Describing the `sandbox` workflow for extension developers.

chrome/common/extensions/docs/examples/howto/sandbox/manifest.json

Index: chrome/common/extensions/docs/examples/howto/sandbox/manifest.json
diff --git a/chrome/common/extensions/docs/examples/howto/sandbox/manifest.json b/chrome/common/extensions/docs/examples/howto/sandbox/manifest.json
new file mode 100644
index 0000000000000000000000000000000000000000..405ba9f99b150c09fb35226172ca32511fb0b4a7
--- /dev/null
+++ b/chrome/common/extensions/docs/examples/howto/sandbox/manifest.json
@@ -0,0 +1,18 @@
+{
+  "name": "Sandboxed Frame",
+  "version": "1.0",
+  "manifest_version": 2,
+  "permissions": ["notifications"],
+  "background": {
+    "page": "eventpage.html",
+    "persistent": false
+  },
+  "browser_action": {
+    "default_icon" : "icon.png",
+    "default_title": "Start Event Page"
+  },
+  "sandbox": {
+    "pages": ["sandbox.html"]
+  },
+  "web_accessible_resources": ["icon.png"]
+}