content: Pass IOSurface references using Mach IPC.

content/common/mac/io_surface_manager_messages.h

+// Copyright 2015 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.
+
+#ifndef CONTENT_COMMON_MAC_IO_SURFACE_MANAGER_MESSAGES_H_
+#define CONTENT_COMMON_MAC_IO_SURFACE_MANAGER_MESSAGES_H_
+
+// Mach IPC messages used for child processes.
+
+// Message IDs.
+// Note: we currently use __LINE__ to give unique IDs to messages.
+// They're unique since all messages are defined in this file.
+#define MACH_MESSAGE_ID() __LINE__
+
+namespace content {
+
+// Messages sent from the child process to the browser.
+
+struct IOSurfaceManagerHostMsg_RegisterIOSurface {
+  enum { ID = MACH_MESSAGE_ID() };
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  mach_msg_port_descriptor_t io_surface_port;
+  int8_t mailbox_name[64];

[Robert Sesek, 2015/05/19 23:26:23]

Perhaps gpu::Mailbox could expose a public typedef for this?

struct gpu::Mailbox {
  using Name = uint8_t[GL_MAILBOX_SIZE_CHROMIUM]
}

So that this could then just use:

gpu::Mailbox::Name mailbox_name;

I am not a gpu/ OWNER though, so should probably ask if that's okay. If not,
then this should at least use mailbox.h's GL_MAILBOX_SIZE_CHROMIUM constant.

[reveman, 2015/05/27 05:03:18]

Good idea. Done.

I also added an IOSurfaceManagerToken typedef to make it a bit less confusing.
We might want to add a base UnguessableId type to base/ as a follow up instead
of relying on gpu/ for this. The typedef seems OK for now as cc::SharedBitmap
does the same thing for cc:SharedBitmapId.

+  int io_surface_id;
+  int client_id;
+};
+
+struct IOSurfaceManagerHostMsg_UnregisterIOSurface {
+  enum { ID = MACH_MESSAGE_ID() };
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  int8_t mailbox_name[64];
+  int io_surface_id;
+  int client_id;
+};
+
+struct IOSurfaceManagerHostMsg_AcquireIOSurface {
+  enum { ID = MACH_MESSAGE_ID() };
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  int8_t mailbox_name[64];
+  int io_surface_id;
+};
+
+// Messages sent from the browser to the child process.
+
+struct IOSurfaceManagerMsg_RegisterIOSurfaceReply {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  boolean_t result;
+};
+
+struct IOSurfaceManagerMsg_AcquireIOSurfaceReply {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  mach_msg_port_descriptor_t io_surface_port;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_MAC_IO_SURFACE_MANAGER_MESSAGES_H_