permissionrequest API for guest Download.

chrome/renderer/resources/extensions/web_view_experimental.js

Index: chrome/renderer/resources/extensions/web_view_experimental.js
diff --git a/chrome/renderer/resources/extensions/web_view_experimental.js b/chrome/renderer/resources/extensions/web_view_experimental.js
index 4f1e201d14eb199fb1252b6f33f9f89c898cca56..7487489a012be3c5ff4af2dd82614d3ba974a53b 100644
--- a/chrome/renderer/resources/extensions/web_view_experimental.js
+++ b/chrome/renderer/resources/extensions/web_view_experimental.js
@@ -16,7 +16,7 @@ var WebView = require('webView').WebView;
 var forEach = require('utils').forEach;
 
 /** @type {Array.<string>} */
-var PERMISSION_TYPES = ['media', 'geolocation', 'pointerLock'];
+var PERMISSION_TYPES = ['download', 'media', 'geolocation', 'pointerLock'];
 
 /** @type {string} */
 var REQUEST_TYPE_NEW_WINDOW = 'newwindow';
@@ -28,6 +28,7 @@ var ERROR_MSG_PERMISSION_ALREADY_DECIDED = '<webview>: ' +
 var EXPOSED_PERMISSION_EVENT_ATTRIBS = [
     'lastUnlockedBySelf',
     'permission',
+    'requestMethod',
     'url',
     'userGesture'
 ];