[System-Keyboard-Lock] Forward navigator functions to RenderFrameHost

third_party/WebKit/public/platform/modules/keyboard_lock/keyboard_lock.mojom

+// Copyright 2017 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.
+
+module blink.mojom;
+
+// The browser side service to process navigator.requestKeyLock() and
+// navigator.cancelKeyLock() web APIs. See http://crbug.com/680809.
+interface KeyboardLockService {
+  // Registers a set of string-formatted key codes
+  // (https://www.w3.org/TR/uievents/#interface-keyboardevent) to the platform
+  // dependent native API, so the web page can receive these key codes
+  // thereafter.
+  // The reason will only be provided if the request is rejected.

[foolip, 2017/04/17 08:46:05]

Does mojo support optional arguments? In that case just an optional string
argument would achieve the same thing, but I don't know what's typical for mojo
interfaces.

[Hzj_jie, 2017/04/18 02:26:08]

mojo supports optional array<string>?. But here we are not sending one string
argument, but a list of strings. Since we always need to do the conversion in
NavigatorKeyboardLock.cpp, using optional argument is not necessary.

[foolip, 2017/04/18 05:10:57]

Acknowledged.

+  RequestKeyLock(array<string> key_codes)
+    => (bool allowed_by_user_or_browser, string reason);
+
+  // Removes all reserved keys. This function is expected to never fail, the
+  // callback indicates the finish of the processing only.
+  CancelKeyLock() => ();
+};