Add a new webstorePrivate API to show a permission prompt for delegated installs

chrome/common/extensions/api/webstore_private.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace":"webstorePrivate",
     "description": "none",
     "types": [
       {
@@ skipping 160 matching lines @@
           },
           {
             "name": "callback",
             "type": "function",
             "optional": true,
             "parameters": []
           }
         ]
       },
       {
+        "name": "showPermissionPromptForDelegatedInstall",
+        "description": "Shows a permission prompt for the given extension, for installing to a different account.",
+        "parameters": [
+          {
+            "name": "details",
+            "type": "object",
+            "properties": {
+              "id": {
+                "type": "string",
+                "description": "The id of the extension to be installled.",
+                "minLength": 32,
+                "maxLength": 32
+              },
+              "manifest": {
+                "type": "string",
+                "description": "A string with the contents of the extension's manifest.json file. During the install process, the browser will check that the downloaded extension's manifest matches what was passed in here.",
+                "minLength": 1
+              },
+              "delegatedUser": {
+                "type": "string",
+                "description": "The display name of the user for whom the extension should be installed."
+              },
+              "iconUrl": {
+                "type": "string",
+                "optional": true,
+                "desciption": "A URL for the image to display in the confirmation dialog"
+              },
+              "iconData": {
+                "type": "string",
+                "optional": true,
+                "description": "An icon as a base64-encoded image, displayed in a confirmation dialog."
+              },
+              "localizedName": {
+                "type": "string",
+                "optional": true,
+                "description": "A string to use instead of the raw value of the 'name' key from manifest.json."
+              }
+            }
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "description": "Called when the user has either accepted/rejected the dialog, or some error occurred (such as invalid manifest or icon image data).",
+            "optional": true,
+            "parameters": [
+              {
+                "name": "result",
+                "$ref": "Result",
+                "description": "A string result code, which will be empty upon success. The possible values in the case of errors include 'unknown_error', 'user_cancelled', 'manifest_error', 'icon_error', 'invalid_id', and 'invalid_icon_url'."
+              }
+            ]
+          }
+        ]
+      },
+      {
         "name": "enableAppLauncher",
         "description": "",
         "parameters": [
           {
             "name": "callback",
             "type": "function",
             "optional": true,
             "parameters": []
           }
         ]
@@ skipping 124 matching lines @@
                 "$ref": "Result",
                 "description": "Whether an attempt to launch an app succeeded, or the reason for failure."
               }
             ]
           }
         ]
       }
     ]
   }
 ]