PPAPI: Make output protection API work with mus+ash

services/ui/public/interfaces/display/output_protection.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 display.mojom;
+
+// An interface for clients that are allowed to control the display output
+// content protection. Multiple clients can request content protection at
+// the same time, and the display will be protection until, all clients
+// are closed or set |desired_method_mask| to 0 with |SetContentProtection|.
+interface OutputProtection {
+  // Queries link status and protection status.
+  QueryContentProtectionStatus(int64 display_id) => (bool success,
+                                                     uint32 link_mask,
+                                                     uint32 protection_mask);
+
+  // Requests the desired protection methods.
+  // |protection_mask| is the desired protection methods, which is a bitmask
+  // of the ContentProtectionMethod values.
+  // Returns true when the protection request has been made.

[sky, 2017/02/13 17:05:01]

Returns true on success? Also, document why it might fail.

[Peng, 2017/02/13 21:14:47]

Done.

+  // When the interface is closed, the content protection mask will be reverted.
+  SetContentProtection(int64 display_id,
+                       uint32 desired_method_mask) => (bool success);
+};