Add an end-to-end test for sign-in profile apps installation

chrome/test/data/extensions/trivial_platform_app/app/manifest.json

Index: chrome/test/data/extensions/trivial_platform_app/app/manifest.json
diff --git a/chrome/test/data/extensions/trivial_platform_app/app/manifest.json b/chrome/test/data/extensions/trivial_platform_app/app/manifest.json
new file mode 100644
index 0000000000000000000000000000000000000000..2ad05d80e2ec25a3fc35610be7a912f195950c81
--- /dev/null
+++ b/chrome/test/data/extensions/trivial_platform_app/app/manifest.json
@@ -0,0 +1,11 @@
+{
+  "name": "Trivial Test Platform App",
+  "version": "1.0",
+  "manifest_version": 2,
+  "description": "The minimalist app for testing purposes.",

[achuithb, 2017/05/08 23:49:46]

A minimal

[emaxx, 2017/05/09 15:03:35]

Done.

+  "app": {
+    "background": {
+      "scripts": ["background.js"]
+    }
+  }
+}