content: Pass IOSurface references using Mach IPC.

content/browser/mach_broker_mac.mm

Index: content/browser/mach_broker_mac.mm
diff --git a/content/browser/mach_broker_mac.mm b/content/browser/mach_broker_mac.mm
index 7c527e55b6f5faaf1e677d2096947c2d4f66a54d..d376d8d930f564b8b8b0af238e9c2e10e7404700 100644
--- a/content/browser/mach_broker_mac.mm
+++ b/content/browser/mach_broker_mac.mm
@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/mach_logging.h"
@@ -29,19 +30,155 @@ namespace content {
 
 namespace {
 
+const mach_msg_id_t kMachBroker_ChildId = 1;

[Daniele Castagna, 2015/05/08 18:58:30]

What about moving the ids inside the structs they identify (e.g:
MachBroker_ChildMsg::Id)

[reveman, 2015/05/09 15:54:54]

Added MACH_MESSAGE_ID macro to latest patch that uses the line number as a
unique ID for each message. This is consistent with how our regular IPC system
generates IDs.

+
 // Mach message structure used in the child as a sending message.
-struct MachBroker_ChildSendMsg {
+struct MachBroker_ChildMsg {
   mach_msg_header_t header;
   mach_msg_body_t body;
   mach_msg_port_descriptor_t child_task_port;
 };
 
-// Complement to the ChildSendMsg, this is used in the parent for receiving
+// Complement to the ChildMsg, this is used in the parent for receiving
 // a message. Contains a message trailer with audit information.
-struct MachBroker_ParentRecvMsg : public MachBroker_ChildSendMsg {
+struct MachBroker_ChildRecvMsg : public MachBroker_ChildMsg {
   mach_msg_audit_trailer_t trailer;
 };
 
+const mach_msg_id_t kMachBroker_RegisterIOSurfaceId = 2;
+
+// Mach message structure used in the child as a sending message.
+struct MachBroker_RegisterIOSurfaceMsg {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  mach_msg_port_descriptor_t io_surface_port;
+  int io_surface_id;
+  int client_id;
+};
+
+// Complement to the RegisterIOSurfaceMsg, this is used in the parent for
+// receiving a message. Contains a message trailer with audit information.
+struct MachBroker_RegisterIOSurfaceRecvMsg
+    : public MachBroker_RegisterIOSurfaceMsg {
+  mach_msg_audit_trailer_t trailer;
+};
+
+// Mach message structure used in the parent as a sending message.
+struct MachBroker_RegisterIOSurfaceReplyMsg {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  boolean_t result;
+};
+
+// Complement to the RegisterIOSurfaceReplyMsg, this is used in the child
+// for receiving a message. Contains a message trailer.
+struct MachBroker_RegisterIOSurfaceReplyRecvMsg
+    : public MachBroker_RegisterIOSurfaceReplyMsg {
+  mach_msg_trailer_t trailer;
+};
+
+const mach_msg_id_t kMachBroker_UnregisterIOSurfaceId = 3;
+
+// Mach message structure used in the child as a sending message.
+struct MachBroker_UnregisterIOSurfaceMsg {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  int io_surface_id;
+  int client_id;
+};
+
+// Complement to the UnregisterIOSurfaceMsg, this is used in the parent for
+// receiving a message. Contains a message trailer with audit information.
+struct MachBroker_UnregisterIOSurfaceRecvMsg
+    : public MachBroker_UnregisterIOSurfaceMsg {
+  mach_msg_audit_trailer_t trailer;
+};
+
+const mach_msg_id_t kMachBroker_AcquireIOSurfaceId = 4;
+
+// Mach message structure used in the child as a sending message.
+struct MachBroker_AcquireIOSurfaceMsg {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  int io_surface_id;
+};
+
+// Complement to the AcquireIOSurfaceMsg, this is used in the parent for
+// receiving a message. Contains a message trailer with audit information.
+struct MachBroker_AcquireIOSurfaceRecvMsg
+    : public MachBroker_AcquireIOSurfaceMsg {
+  mach_msg_audit_trailer_t trailer;
+};
+
+// Mach message structure used in the parent as a sending message.
+struct MachBroker_AcquireIOSurfaceReplyMsg {
+  mach_msg_header_t header;
+  mach_msg_body_t body;
+  mach_msg_port_descriptor_t io_surface_port;
+};
+
+// Complement to the AcquireIOSurfaceReplyMsg, this is used in the child for
+// receiving a message. Contains a message trailer.
+struct MachBroker_AcquireIOSurfaceReplyRecvMsg
+    : public MachBroker_AcquireIOSurfaceReplyMsg {
+  mach_msg_trailer_t trailer;
+};
+
+// Returns the Mach port name to use when sending or receiving messages.
+// Does the Right Thing in the browser and in child processes.
+std::string GetMachPortName() {
+  const base::CommandLine* command_line =
+      base::CommandLine::ForCurrentProcess();
+  const bool is_child = command_line->HasSwitch(switches::kProcessType);
+
+  // In non-browser (child) processes, use the parent's pid.
+  const pid_t pid = is_child ? getppid() : getpid();
+  return base::StringPrintf("%s.rohitfork.%d", base::mac::BaseBundleID(), pid);
+}
+
+struct ChildSendPortLazyInstanceTraits
+    : public base::internal::LeakyLazyInstanceTraits<
+          base::mac::ScopedMachSendRight> {
+  static base::mac::ScopedMachSendRight* New(void* instance) {
+    mach_port_t send_port = MACH_PORT_NULL;
+    // Look up the named MachBroker port that's been registered with the
+    // bootstrap server.
+    kern_return_t kr = bootstrap_look_up(
+        bootstrap_port, const_cast<char*>(GetMachPortName().c_str()),
+        &send_port);
+    if (kr != KERN_SUCCESS)
+      BOOTSTRAP_LOG(ERROR, kr) << "bootstrap_look_up";
+
+    // Use placement new to initialize our instance in our preallocated space.
+    return new (instance) base::mac::ScopedMachSendRight(send_port);
+  }
+};
+
+base::LazyInstance<base::mac::ScopedMachSendRight,
+                   ChildSendPortLazyInstanceTraits> g_child_send_port =
+    LAZY_INSTANCE_INITIALIZER;
+
+struct ChildReceivePortLazyInstanceTraits
+    : public base::internal::LeakyLazyInstanceTraits<
+          base::mac::ScopedMachSendRight> {
+  static base::mac::ScopedMachSendRight* New(void* instance) {
+    mach_port_t receive_port = MACH_PORT_NULL;
+    kern_return_t kr = mach_port_allocate(
+        mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &receive_port);
+    if (kr != KERN_SUCCESS)
+      MACH_LOG(ERROR, kr) << "mach_port_allocate";
+
+    // Use placement new to initialize our instance in our preallocated space.
+    return new (instance) base::mac::ScopedMachSendRight(receive_port);
+  }
+};
+
+base::LazyInstance<base::mac::ScopedMachSendRight,
+                   ChildReceivePortLazyInstanceTraits> g_child_receive_port =
+    LAZY_INSTANCE_INITIALIZER;
+
+base::LazyInstance<base::Lock> g_child_lock = LAZY_INSTANCE_INITIALIZER;
+
 }  // namespace
 
 class MachListenerThreadDelegate : public base::PlatformThread::Delegate {
@@ -79,14 +216,20 @@ class MachListenerThreadDelegate : public base::PlatformThread::Delegate {
     // is deprecated, this has to be wraped in an ObjC interface.
     NSPort* ns_port = [NSMachPort portWithMachPort:port
                                            options:NSMachPortDeallocateNone];
-    NSString* name = base::SysUTF8ToNSString(broker_->GetMachPortName());
+    NSString* name = base::SysUTF8ToNSString(GetMachPortName());
     return [[NSMachBootstrapServer sharedInstance] registerPort:ns_port
                                                            name:name];
   }
 
   // Implement |PlatformThread::Delegate|.
   void ThreadMain() override {
-    MachBroker_ParentRecvMsg msg;
+    union {
+      mach_msg_header_t header;
+      MachBroker_ChildRecvMsg child;
+      MachBroker_RegisterIOSurfaceRecvMsg register_io_surface;
+      MachBroker_UnregisterIOSurfaceRecvMsg unregister_io_surface;
+      MachBroker_AcquireIOSurfaceRecvMsg acquire_io_surface;
+    } msg;
     bzero(&msg, sizeof(msg));
     msg.header.msgh_size = sizeof(msg);
     msg.header.msgh_local_port = server_port_.get();
@@ -104,19 +247,80 @@ class MachListenerThreadDelegate : public base::PlatformThread::Delegate {
                           MACH_MSG_TIMEOUT_NONE,
                           MACH_PORT_NULL)) == KERN_SUCCESS) {
       // Use the kernel audit information to make sure this message is from
-      // a task that this process spawned. The kernel audit token contains the
-      // unspoofable pid of the task that sent the message.
-      //
+      // a task that this process spawned. The kernel audit token contains
+      // the unspoofable pid of the task that sent the message.
+      mach_msg_audit_trailer_t* trailer =
+          reinterpret_cast<mach_msg_audit_trailer_t*>(
+              reinterpret_cast<vm_address_t>(&msg.header) +
+              round_msg(msg.header.msgh_size));
       // TODO(rsesek): In the 10.7 SDK, there's audit_token_to_pid().
       pid_t child_pid;
-      audit_token_to_au32(msg.trailer.msgh_audit,
-          NULL, NULL, NULL, NULL, NULL, &child_pid, NULL, NULL);
-
-      mach_port_t child_task_port = msg.child_task_port.name;
+      audit_token_to_au32(trailer->msgh_audit, NULL, NULL, NULL, NULL, NULL,
+                          &child_pid, NULL, NULL);
 
-      // Take the lock and update the broker information.
+      // Take the lock.
       base::AutoLock lock(broker_->GetLock());
-      broker_->FinalizePid(child_pid, child_task_port);
+
+      switch (msg.header.msgh_id) {
+        case kMachBroker_ChildId: {
+          mach_port_t child_task_port = msg.child.child_task_port.name;
+
+          // Update the broker information.
+          broker_->FinalizePid(child_pid, child_task_port);
+        } break;
+        case kMachBroker_RegisterIOSurfaceId: {
+          mach_port_t io_surface_port =
+              msg.register_io_surface.io_surface_port.name;
+          int io_surface_id = msg.register_io_surface.io_surface_id;
+          int client_id = msg.register_io_surface.client_id;
+
+          bool result = broker_->RegisterIOSurface(child_pid, io_surface_id,
+                                                   client_id, io_surface_port);
+
+          MachBroker_RegisterIOSurfaceReplyMsg reply;
+          bzero(&reply, sizeof(reply));
+          reply.header.msgh_bits = MACH_MSGH_BITS_REMOTE(msg.header.msgh_bits);
+          reply.header.msgh_remote_port = msg.header.msgh_remote_port;
+          reply.header.msgh_size = sizeof(reply);
+          reply.result = result;
+          kern_return_t kr = mach_msg(
+              &reply.header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, sizeof(reply),
+              0, MACH_PORT_NULL, 100 /*milliseconds*/, MACH_PORT_NULL);
+          if (kr != KERN_SUCCESS) {
+            MACH_LOG(ERROR, kr) << "mach_msg";
+          }
+
+        } break;
+        case kMachBroker_UnregisterIOSurfaceId: {
+          int io_surface_id = msg.unregister_io_surface.io_surface_id;
+          int client_id = msg.unregister_io_surface.client_id;
+
+          broker_->UnregisterIOSurface(child_pid, io_surface_id, client_id);
+        } break;
+        case kMachBroker_AcquireIOSurfaceId: {
+          int io_surface_id = msg.acquire_io_surface.io_surface_id;
+
+          mach_port_t io_surface_port =
+              broker_->AcquireIOSurface(child_pid, io_surface_id);
+
+          MachBroker_AcquireIOSurfaceReplyMsg reply;
+          bzero(&reply, sizeof(reply));
+          reply.header.msgh_bits = MACH_MSGH_BITS_REMOTE(msg.header.msgh_bits) |
+                                   MACH_MSGH_BITS_COMPLEX;
+          reply.header.msgh_remote_port = msg.header.msgh_remote_port;
+          reply.header.msgh_size = sizeof(reply);
+          reply.body.msgh_descriptor_count = 1;
+          reply.io_surface_port.name = io_surface_port;
+          reply.io_surface_port.disposition = MACH_MSG_TYPE_COPY_SEND;
+          reply.io_surface_port.type = MACH_MSG_PORT_DESCRIPTOR;
+          kern_return_t kr = mach_msg(
+              &reply.header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, sizeof(reply),
+              0, MACH_PORT_NULL, 100 /*milliseconds*/, MACH_PORT_NULL);
+          if (kr != KERN_SUCCESS) {
+            MACH_LOG(ERROR, kr) << "mach_msg";
+          }
+        } break;
+      }
     }
 
     MACH_LOG(ERROR, kr) << "mach_msg";
@@ -132,33 +336,46 @@ class MachListenerThreadDelegate : public base::PlatformThread::Delegate {
   DISALLOW_COPY_AND_ASSIGN(MachListenerThreadDelegate);
 };
 
+MachBroker::MachPortSet::MachPortSet()
+    : is_gpu_process(false), task_port(MACH_PORT_NULL) {
+}
+
+MachBroker::MachPortSet::MachPortSet(bool is_gpu_process)
+    : is_gpu_process(is_gpu_process), task_port(MACH_PORT_NULL) {
+}
+
+MachBroker::MachPortSet::~MachPortSet() {
+}
+
 bool MachBroker::ChildSendTaskPortToParent() {
-  // Look up the named MachBroker port that's been registered with the
-  // bootstrap server.
-  mach_port_t parent_port;
-  kern_return_t kr = bootstrap_look_up(bootstrap_port,
-      const_cast<char*>(GetMachPortName().c_str()), &parent_port);
-  if (kr != KERN_SUCCESS) {
-    BOOTSTRAP_LOG(ERROR, kr) << "bootstrap_look_up";
+  base::AutoLock lock(g_child_lock.Get());
+
+  mach_port_t child_send_port = g_child_send_port.Get();
+  if (child_send_port == MACH_PORT_NULL)
+    return false;
+
+  // Make sure we have valid receive port before we send the check in message.
+  mach_port_t child_receive_port = g_child_receive_port.Get();
+  if (child_receive_port == MACH_PORT_NULL)
     return false;
-  }
-  base::mac::ScopedMachSendRight scoped_right(parent_port);
 
   // Create the check in message. This will copy a send right on this process'
   // (the child's) task port and send it to the parent.
-  MachBroker_ChildSendMsg msg;
+  MachBroker_ChildMsg msg;
   bzero(&msg, sizeof(msg));
   msg.header.msgh_bits = MACH_MSGH_BITS_REMOTE(MACH_MSG_TYPE_COPY_SEND) |
                          MACH_MSGH_BITS_COMPLEX;
-  msg.header.msgh_remote_port = parent_port;
+  msg.header.msgh_remote_port = child_send_port;
   msg.header.msgh_size = sizeof(msg);
+  msg.header.msgh_id = kMachBroker_ChildId;
   msg.body.msgh_descriptor_count = 1;
   msg.child_task_port.name = mach_task_self();
   msg.child_task_port.disposition = MACH_MSG_TYPE_PORT_SEND;
   msg.child_task_port.type = MACH_MSG_PORT_DESCRIPTOR;
 
-  kr = mach_msg(&msg.header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, sizeof(msg),
-      0, MACH_PORT_NULL, 100 /*milliseconds*/, MACH_PORT_NULL);
+  kern_return_t kr =
+      mach_msg(&msg.header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, sizeof(msg), 0,
+               MACH_PORT_NULL, 100 /*milliseconds*/, MACH_PORT_NULL);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "mach_msg";
     return false;
@@ -167,6 +384,102 @@ bool MachBroker::ChildSendTaskPortToParent() {
   return true;
 }
 
+bool MachBroker::ChildRegisterIOSurfaceWithParent(int io_surface_id,
+                                                  int client_id,
+                                                  mach_port_t io_surface_port) {
+  base::AutoLock lock(g_child_lock.Get());
+
+  mach_port_t child_receive_port = g_child_receive_port.Get();
+
+  // Deallocate the right after sending a copy to the parent.
+  base::mac::ScopedMachSendRight io_surface_send_right(io_surface_port);
+
+  union {
+    MachBroker_RegisterIOSurfaceMsg request;
+    MachBroker_RegisterIOSurfaceReplyRecvMsg reply;
+  } msg;
+  bzero(&msg, sizeof(msg));
+  msg.request.header.msgh_bits =
+      MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND_ONCE) |
+      MACH_MSGH_BITS_COMPLEX;
+  msg.request.header.msgh_remote_port = g_child_send_port.Get();
+  msg.request.header.msgh_local_port = child_receive_port;
+  msg.request.header.msgh_size = sizeof(msg.request);
+  msg.request.header.msgh_id = kMachBroker_RegisterIOSurfaceId;
+  msg.request.body.msgh_descriptor_count = 1;
+  msg.request.io_surface_port.name = io_surface_port;
+  msg.request.io_surface_port.disposition = MACH_MSG_TYPE_COPY_SEND;
+  msg.request.io_surface_port.type = MACH_MSG_PORT_DESCRIPTOR;
+  msg.request.io_surface_id = io_surface_id;
+  msg.request.client_id = client_id;
+
+  kern_return_t kr =
+      mach_msg(&msg.request.header, MACH_SEND_MSG | MACH_RCV_MSG,
+               sizeof(msg.request), sizeof(msg.reply), child_receive_port,
+               MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+  if (kr != KERN_SUCCESS) {
+    MACH_LOG(ERROR, kr) << "mach_msg";
+    return false;
+  }
+
+  return msg.reply.result;
+}
+
+bool MachBroker::ChildUnregisterIOSurfaceWithParent(int io_surface_id,
+                                                    int client_id) {
+  base::AutoLock lock(g_child_lock.Get());
+
+  MachBroker_UnregisterIOSurfaceMsg msg;
+  bzero(&msg, sizeof(msg));
+  msg.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
+  msg.header.msgh_remote_port = g_child_send_port.Get();
+  msg.header.msgh_local_port = MACH_PORT_NULL;
+  msg.header.msgh_size = sizeof(msg);
+  msg.header.msgh_id = kMachBroker_UnregisterIOSurfaceId;
+  msg.io_surface_id = io_surface_id;
+  msg.client_id = client_id;
+
+  kern_return_t kr =
+      mach_msg(&msg.header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, sizeof(msg), 0,
+               MACH_PORT_NULL, 100 /*milliseconds*/, MACH_PORT_NULL);
+  if (kr != KERN_SUCCESS) {
+    MACH_LOG(ERROR, kr) << "mach_msg";
+    return false;
+  }
+
+  return true;
+}
+
+mach_port_t MachBroker::ChildAcquireIOSurfaceFromParent(int io_surface_id) {
+  base::AutoLock lock(g_child_lock.Get());
+
+  mach_port_t child_receive_port = g_child_receive_port.Get();
+
+  union {
+    MachBroker_AcquireIOSurfaceMsg request;
+    MachBroker_AcquireIOSurfaceReplyRecvMsg reply;
+  } msg;
+  bzero(&msg, sizeof(msg));
+  msg.request.header.msgh_bits =
+      MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND_ONCE);
+  msg.request.header.msgh_remote_port = g_child_send_port.Get();
+  msg.request.header.msgh_local_port = child_receive_port;
+  msg.request.header.msgh_size = sizeof(msg.request);
+  msg.request.header.msgh_id = kMachBroker_AcquireIOSurfaceId;
+  msg.request.io_surface_id = io_surface_id;
+
+  kern_return_t kr =
+      mach_msg(&msg.request.header, MACH_SEND_MSG | MACH_RCV_MSG,
+               sizeof(msg.request), sizeof(msg.reply), child_receive_port,
+               MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+  if (kr != KERN_SUCCESS) {
+    MACH_LOG(ERROR, kr) << "mach_msg";
+    return MACH_PORT_NULL;
+  }
+
+  return msg.reply.io_surface_port.name;
+}
+
 MachBroker* MachBroker::GetInstance() {
   return Singleton<MachBroker, LeakySingletonTraits<MachBroker> >::get();
 }
@@ -196,11 +509,12 @@ void MachBroker::EnsureRunning() {
 }
 
 void MachBroker::AddPlaceholderForPid(base::ProcessHandle pid,
-                                      int child_process_id) {
+                                      int child_process_id,
+                                      bool is_gpu_process) {
   lock_.AssertAcquired();
 
   DCHECK_EQ(0u, mach_map_.count(pid));
-  mach_map_[pid] = MACH_PORT_NULL;
+  mach_map_[pid] = MachPortSet(is_gpu_process);
   child_process_id_map_[child_process_id] = pid;
 }
 
@@ -209,7 +523,7 @@ mach_port_t MachBroker::TaskForPid(base::ProcessHandle pid) const {
   MachBroker::MachMap::const_iterator it = mach_map_.find(pid);
   if (it == mach_map_.end())
     return MACH_PORT_NULL;
-  return it->second;
+  return it->second.task_port;
 }
 
 void MachBroker::BrowserChildProcessHostDisconnected(
@@ -254,9 +568,8 @@ void MachBroker::FinalizePid(base::ProcessHandle pid,
     return;
   }
 
-  DCHECK(it->second == MACH_PORT_NULL);
-  if (it->second == MACH_PORT_NULL)
-    it->second = task_port;
+  if (it->second.task_port == MACH_PORT_NULL)
+    it->second.task_port = task_port;
 }
 
 void MachBroker::InvalidateChildProcessId(int child_process_id) {
@@ -268,23 +581,107 @@ void MachBroker::InvalidateChildProcessId(int child_process_id) {
 
   MachMap::iterator mach_it = mach_map_.find(it->second);
   if (mach_it != mach_map_.end()) {
-    kern_return_t kr = mach_port_deallocate(mach_task_self(),
-                                            mach_it->second);
+    kern_return_t kr =
+        mach_port_deallocate(mach_task_self(), mach_it->second.task_port);
     MACH_LOG_IF(WARNING, kr != KERN_SUCCESS, kr) << "mach_port_deallocate";
+    for (const auto& io_surface_port : mach_it->second.io_surface_ports) {
+      kr = mach_port_deallocate(mach_task_self(), io_surface_port.second);
+      MACH_LOG_IF(WARNING, kr != KERN_SUCCESS, kr) << "mach_port_deallocate";
+    }
     mach_map_.erase(mach_it);
   }
   child_process_id_map_.erase(it);
 }
 
-// static
-std::string MachBroker::GetMachPortName() {
-  const base::CommandLine* command_line =
-      base::CommandLine::ForCurrentProcess();
-  const bool is_child = command_line->HasSwitch(switches::kProcessType);
+bool MachBroker::RegisterIOSurface(base::ProcessHandle pid,
+                                   int io_surface_id,
+                                   int client_id,
+                                   mach_port_t io_surface_port) {
+  lock_.AssertAcquired();
 
-  // In non-browser (child) processes, use the parent's pid.
-  const pid_t pid = is_child ? getppid() : getpid();
-  return base::StringPrintf("%s.rohitfork.%d", base::mac::BaseBundleID(), pid);
+  MachMap::iterator mach_it = mach_map_.find(pid);
+  if (mach_it == mach_map_.end()) {
+    // Do nothing for unknown pids.
+    LOG(ERROR) << "Unknown process " << pid << " is sending Mach IPC messages!";
+    return false;
+  }
+
+  if (!mach_it->second.is_gpu_process) {
+    LOG(ERROR) << "Illegal message from non-GPU process!";
+    return false;
+  }
+
+  ChildProcessIdMap::iterator it = child_process_id_map_.find(client_id);
+  if (it == child_process_id_map_.end())
+    return false;
+
+  MachMap::iterator client_it = mach_map_.find(it->second);
+  if (client_it == mach_map_.end()) {
+    LOG(ERROR) << "Unknown client process " << it->second;
+    return false;
+  }
+
+  if (client_it->second.io_surface_ports.count(io_surface_id)) {
+    LOG(ERROR) << "IOSurface " << io_surface_id << " already exists!";
+    return false;
+  }
+
+  client_it->second.io_surface_ports[io_surface_id] = io_surface_port;
+  return true;
+}
+
+void MachBroker::UnregisterIOSurface(base::ProcessHandle pid,
+                                     int io_surface_id,
+                                     int client_id) {
+  lock_.AssertAcquired();
+
+  MachMap::iterator mach_it = mach_map_.find(pid);
+  if (mach_it == mach_map_.end()) {
+    // Do nothing for unknown pids.
+    LOG(ERROR) << "Unknown process " << pid << " is sending Mach IPC messages!";
+    return;
+  }
+
+  if (!mach_it->second.is_gpu_process) {
+    LOG(ERROR) << "Illegal message from non-GPU process!";
+    return;
+  }
+
+  ChildProcessIdMap::iterator it = child_process_id_map_.find(client_id);
+  if (it == child_process_id_map_.end())
+    return;
+
+  mach_it = mach_map_.find(it->second);
+  if (mach_it != mach_map_.end()) {
+    auto io_surface_mach_it =
+        mach_it->second.io_surface_ports.find(io_surface_id);
+    if (io_surface_mach_it != mach_it->second.io_surface_ports.end()) {
+      kern_return_t kr =
+          mach_port_deallocate(mach_task_self(), io_surface_mach_it->second);
+      MACH_LOG_IF(WARNING, kr != KERN_SUCCESS, kr) << "mach_port_deallocate";
+      mach_it->second.io_surface_ports.erase(io_surface_mach_it);
+    }
+  }
+}
+
+mach_port_t MachBroker::AcquireIOSurface(base::ProcessHandle pid,
+                                         int io_surface_id) {
+  lock_.AssertAcquired();
+
+  MachMap::iterator it = mach_map_.find(pid);
+  if (it == mach_map_.end()) {
+    // Do nothing for unknown pids.
+    LOG(ERROR) << "Unknown process " << pid << " is sending Mach IPC messages!";
+    return MACH_PORT_NULL;
+  }
+
+  auto io_surface_mach_it = it->second.io_surface_ports.find(io_surface_id);
+  if (io_surface_mach_it == it->second.io_surface_ports.end()) {
+    LOG(ERROR) << "Invalid Id for IOSurface " << io_surface_id;
+    return MACH_PORT_NULL;
+  }
+
+  return io_surface_mach_it->second;
 }
 
 void MachBroker::RegisterNotifications() {