ozone: ClientPixmapManager passes VGEM fd from browser to renderer.

content/child/child_io_surface_manager_mac.cc

 // 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.
 
 #include "content/child/child_io_surface_manager_mac.h"
 
 #include "base/mac/mach_logging.h"
 #include "content/common/mac/io_surface_manager_messages.h"
 
 namespace content {
@@ skipping 78 matching lines @@
     MACH_LOG(ERROR, kr) << "mach_msg";
   }
 }
 
 IOSurfaceRef ChildIOSurfaceManager::AcquireIOSurface(
     IOSurfaceId io_surface_id) {
   DCHECK(service_port_.is_valid());
 
   // A valid token is required to acquire an IOSurface. This will wait for a
   // valid token if one has not yet been set.
   set_token_event_.Wait();

[dshwang, 2015/08/21 13:04:10]

reveman, it should require "base::ThreadRestrictions::ScopedAllowWait
allow_wait;" not to crash, right?

[reveman, 2015/08/21 14:40:31]

Only if this is called on a thread where wait is not allowed. Is it? We
typically call this on a worker thread.

[dshwang, 2015/08/21 15:21:18]

Ah, compositor creates GMB in worker thread, not impl thread. sorry for
misleading.
By the way, GMB is created in renderer_gpu_video_accelerator_factories.cc and
CreateGpuMemoryBufferImageCHROMIUM in gles2_implementation also.
So I think each platform GBM implementation needs
base::ThreadRestrictions::ScopedAllowWait

[dshwang, 2015/08/21 15:56:50]

And crash happens in worker thread in chromeos. For some reasons, worker thread
of chromeos is not allowed to wait by default. Is MacOS fine?

[dshwang, 2015/08/21 18:38:37]

Added.

-#if !defined(NDEBUG)
+#if DCHECK_IS_ON()
   DCHECK(!(set_token_thread_id_ == base::PlatformThread::CurrentRef()));
 #endif
   DCHECK(!token_.IsZero());
 
   mach_port_t reply_port;
   kern_return_t kr = mach_port_allocate(mach_task_self(),
                                         MACH_PORT_RIGHT_RECEIVE, &reply_port);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "mach_port_allocate";
     return nullptr;
@@ skipping 31 matching lines @@
   return IOSurfaceLookupFromMachPort(scoped_io_surface_right);
 }
 
 ChildIOSurfaceManager::ChildIOSurfaceManager()
     : set_token_event_(true, false) {}
 
 ChildIOSurfaceManager::~ChildIOSurfaceManager() {
 }
 
 }  // namespace content