Implement native GMB backbuffers in the GLES2 Command Decoder.

gpu/ipc/service/gpu_memory_buffer_factory_io_surface.cc

 // Copyright 2014 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 "gpu/ipc/service/gpu_memory_buffer_factory_io_surface.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "ui/gfx/buffer_format_util.h"
@@ skipping 14 matching lines @@
     const gfx::Size& size,
     gfx::BufferFormat format,
     gfx::BufferUsage usage,
     int client_id,
     SurfaceHandle surface_handle) {
   base::ScopedCFTypeRef<IOSurfaceRef> io_surface(
       gfx::CreateIOSurface(size, format));
   if (!io_surface)
     return gfx::GpuMemoryBufferHandle();
 
-  {
+  // A GpuMemoryBuffer with client_id = 0 behaves like anonymous shared memory.
+  if (client_id != 0) {
     base::AutoLock lock(io_surfaces_lock_);
 
     IOSurfaceMapKey key(id, client_id);
     DCHECK(io_surfaces_.find(key) == io_surfaces_.end());
     io_surfaces_[key] = io_surface;
   }
 
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::IO_SURFACE_BUFFER;
   handle.id = id;
@@ skipping 33 matching lines @@
     return scoped_refptr<gl::GLImage>();
 
   scoped_refptr<gl::GLImageIOSurface> image(
       new gl::GLImageIOSurface(size, internalformat));
   if (!image->Initialize(it->second.get(), handle.id, format))
     return scoped_refptr<gl::GLImage>();
 
   return image;
 }
 
+scoped_refptr<gl::GLImage>
+GpuMemoryBufferFactoryIOSurface::CreateAnonymousImage(const gfx::Size& size,
+                                                      gfx::BufferFormat format,
+                                                      unsigned internalformat) {
+  // Note that the GpuMemoryBufferId and child id don't matter since the texture
+  // will never be directly exposed to other processes, only via a mailbox.
+  int gmb_id = 0;
+  int client_id = 0;
+  gfx::GpuMemoryBufferHandle handle = CreateGpuMemoryBuffer(
+      gfx::GpuMemoryBufferId(gmb_id), size, format, gfx::BufferUsage::SCANOUT,
+      client_id, gpu::kNullSurfaceHandle);
+
+  base::ScopedCFTypeRef<IOSurfaceRef> io_surface;
+  io_surface.reset(IOSurfaceLookupFromMachPort(handle.mach_port.get()));
+  DCHECK_NE(nullptr, io_surface.get());
+  scoped_refptr<gl::GLImageIOSurface> image(
+      new gl::GLImageIOSurface(size, internalformat));
+  if (!image->Initialize(io_surface.get(), handle.id, format))
+    return scoped_refptr<gl::GLImage>();
+  return image;
+}
+
 }  // namespace gpu