feedback UI: use native window controls on Mac

chrome/common/extensions/api/feedback_private.idl

 // Copyright 2013 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.
 
 // Use the <code>chrome.feedbackPrivate</code> API to provide Chrome [OS]
 // feedback to the Google Feedback servers.
 namespace feedbackPrivate {
 
   dictionary AttachedFile {
     DOMString name;
@@ skipping 53 matching lines @@
     // True if we have permission to add histograms to this feedback report.
     boolean sendHistograms;
 
     // Optional feedback UI flow. Default is the regular user flow.
     FeedbackFlow? flow;
 
     // TODO(rkc): Remove these once we have bindings to send blobs to Chrome.
     // Used internally to store the blob uuid after parameter customization.
     DOMString? attachedFileBlobUuid;
     DOMString? screenshotBlobUuid;
+
+    boolean useSystemWindowFrame;

[afakhry, 2016/08/30 16:27:04]

Nit: Please add a comment.

   };
 
   // Status of the sending of a feedback report.
   enum Status {success, delayed};
 
   // Result of presenting the user with a prompt to download SRT.
   enum SrtPromptResult {
     // User clicked the "Learn More" button.
     accepted,
 
@@ skipping 32 matching lines @@
   };
 
   interface Events {
     // Fired when the a user requests the launch of the feedback UI. We're
     // using an event for this versus using the override API since we want
     // to be invoked, but not showing a UI, so the feedback extension can
     // take a screenshot of the user's desktop.
     static void onFeedbackRequested(FeedbackInfo feedback);
   };
 };