content: Pass IOSurface references using Mach IPC.

content/browser/mach_broker_mac.h

Index: content/browser/mach_broker_mac.h
diff --git a/content/browser/mach_broker_mac.h b/content/browser/mach_broker_mac.h
index fb9f3efbf17b4dca105e4d683993ad368a72d4f7..0299e9790904d02d48f87d9ccf6d47e1d35e2a59 100644
--- a/content/browser/mach_broker_mac.h
+++ b/content/browser/mach_broker_mac.h
@@ -44,6 +44,20 @@ class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
   // and false if otherwise.
   static bool ChildSendTaskPortToParent();
 
+  // Register an IO surface for use in child process with |client_id|.
+  static bool ChildRegisterIOSurfaceWithParent(int io_surface_id,
+                                               int client_id,
+                                               mach_port_t io_surface_port);
+
+  // Unregister an IO surface.
+  static bool ChildUnregisterIOSurfaceWithParent(int io_surface_id,
+                                                 int client_id);
+
+  // Acquire IO surface reference for a registered IO surface. This will only
+  // succeed if the IO surface has been registered for use in the current
+  // process.

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

What happens if it doesn't succeed? Does it return MACH_PORT_NULL?

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

Yes, added this to the comment.

+  static mach_port_t ChildAcquireIOSurfaceFromParent(int io_surface_id);
+
   // Returns the global MachBroker.
   static MachBroker* GetInstance();
 
@@ -61,7 +75,9 @@ class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
   // Callers are expected to later update the port with FinalizePid().  Callers
   // MUST acquire the lock given by GetLock() before calling this method (and
   // release the lock afterwards).
-  void AddPlaceholderForPid(base::ProcessHandle pid, int child_process_id);
+  void AddPlaceholderForPid(base::ProcessHandle pid,
+                            int child_process_id,
+                            bool is_gpu_process);
 
   // Implement |ProcessMetrics::PortProvider|.
   mach_port_t TaskForPid(base::ProcessHandle process) const override;
@@ -94,9 +110,26 @@ class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
   // Removes all mappings belonging to |child_process_id| from the broker.
   void InvalidateChildProcessId(int child_process_id);
 
-  // Returns the Mach port name to use when sending or receiving messages.
-  // Does the Right Thing in the browser and in child processes.
-  static std::string GetMachPortName();
+  // Register an IO surface for use in child process with |client_id|.
+  // Callers MUST acquire the lock given by GetLock() before calling this
+  // method (and release the lock afterwards).
+  bool RegisterIOSurface(base::ProcessHandle pid,

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

Are there annotations used in chromium for suggesting that a methods require a
locks?

Something like:
 bool RegisterIOSurface(...) EXCLUSIVE_LOCKS_REQUIRED(lock_);

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

No, that that I know. That'd be nice but I'm afraid the comment will have to do.

+                         int io_surface_id,
+                         int client_id,
+                         mach_port_t io_surface_port);
+
+  // Unregister an IO surface. Callers MUST acquire the lock given by GetLock()
+  // before calling this method (and release the lock afterwards).
+  void UnregisterIOSurface(base::ProcessHandle pid,
+                           int io_surface_id,
+                           int client_id);
+
+  // Acquire IO surface reference for a registered IO surface. This will
+  // only succeed if the IO surface is registered for use in |pid|. Callers
+  // MUST acquire the lock given by GetLock() before calling this method
+  // (and release the lock afterwards).
+  mach_port_t AcquireIOSurface(base::ProcessHandle pid, int io_surface_id);
+
   // Callback used to register notifications on the UI thread.
   void RegisterNotifications();
 
@@ -108,7 +141,16 @@ class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
   NotificationRegistrar registrar_;
 
   // Stores mach info for every process in the broker.
-  typedef std::map<base::ProcessHandle, mach_port_t> MachMap;
+  struct MachPortSet {
+    MachPortSet();
+    explicit MachPortSet(bool is_gpu_process);
+    ~MachPortSet();
+
+    bool is_gpu_process;
+    mach_port_t task_port;
+    std::map<int, mach_port_t> io_surface_ports;
+  };
+  typedef std::map<base::ProcessHandle, MachPortSet> MachMap;
   MachMap mach_map_;
 
   // Stores the Child process unique id (RenderProcessHost ID) for every