Add a test for requesting mount via a context menu in Files app.

ui/file_manager/integration_tests/testing_provider/manifest.json

Index: ui/file_manager/integration_tests/testing_provider/manifest.json
diff --git a/chrome/test/data/extensions/api_test/file_browser/mount_test/manifest.json b/ui/file_manager/integration_tests/testing_provider/manifest.json
similarity index 74%
copy from chrome/test/data/extensions/api_test/file_browser/mount_test/manifest.json
copy to ui/file_manager/integration_tests/testing_provider/manifest.json
index 9bc018ca6e2674bfb3f7e7fad0ceaa6a5ba43800..cc6074646b8192914ce78651eafa92c896582fc1 100644
--- a/chrome/test/data/extensions/api_test/file_browser/mount_test/manifest.json
+++ b/ui/file_manager/integration_tests/testing_provider/manifest.json
@@ -1,15 +1,18 @@
 {
   // chrome-extension://pkplfbidichfdicaijlchgnapepdginl
   "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtDfX9dHNh948bt00YhZBm3P6E5QLaOt+v8kXVtibQfiPtOD2FTScB/f0wX/EQWVO7BkaSOsRkTPcPIgocyMPYr2FLgqGLFlYT9nQpKJZUFNF5oJ5rG6Nv7ppf4zEB3j6da1IBRTz2yOZ+6O1TMZxol/V62/QcqrJeggsHTEPGLdr9Ua4b1Ka0xKJnJngZljsbw93FI1o+P9dAh5BS6wTPiZI/vmJVjvMTkSTnaZ3n9Go2t7A0XLcSxLcVyuLAd2mAvSN0mIviOukdM66wr7llif71nKuUt+4qvlr/r9HfwzN6pA4jkwhtS1UD+3CmB+wsHwsnohNcuu4FIQ6rgq/7QIDAQAB",
-  "name": "chrome.fileManagerPrivate Mount Tests",
+  "name": "Testing Provider",
   "version": "0.1",
   "manifest_version": 2,
-  "description": "Tests of chrome.fileManagerPrivate component extension methods that communicate with MountLibrary",
+  "description": "Testing Provider",
+  "permissions": [
+    "fileSystemProvider"
+  ],
+  "file_system_provider_capabilities": {
+    "source": "network",
+    "multiple_mounts": false
+  },
   "background": {
     "scripts": ["background.js"]
-  },
-  "permissions": [
-    "fileManagerPrivate"
-   ]
+  }
 }
-