1 files changed, 42 insertions, 0 deletions
diff --git a/layout/ipc/PVsync.ipdl b/layout/ipc/PVsync.ipdl
new file mode 100644
index 000000000..5d31e34d4
--- /dev/null
+++ b/layout/ipc/PVsync.ipdl
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBackground;
+
+using class mozilla::TimeStamp from "mozilla/TimeStamp.h";
+
+namespace mozilla {
+namespace layout {
+
+/*
+ * The PVsync is a sub-protocol in PBackground and it is used to notify
+ * the vsync event from chrome to content process. It also provides the
+ * interfaces for content to observe/unobserve vsync event notifications.
+ */
+async protocol PVsync
+{
+  manager PBackground;
+
+child:
+  // Send vsync event from chrome to content process.
+  async Notify(TimeStamp aVsyncTimestamp) compress;
+
+  // Send the vsync rate to the content process.
+  async VsyncRate(float aVsyncRate);
+
+parent:
+  // Content process use these messages to acquire the vsync event.
+  async Observe();
+  async Unobserve();
+  async RequestVsyncRate();
+
+  // This message is never sent. Each PVsync actor will stay alive as long as
+  // its PBackground manager.
+  async __delete__();
+};
+
+} // namespace layout
+} // namespace mozilla
+