gpu: Reuse existing code for shared memory allocation.

gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.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/client/gpu_memory_buffer_impl_shared_memory.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 60 matching lines @@
   base::SharedMemory shared_memory;
   if (!shared_memory.CreateAnonymous(buffer_size))
     return gfx::GpuMemoryBufferHandle();
 
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::SHARED_MEMORY_BUFFER;
   handle.id = id;
   handle.offset = 0;
   handle.stride = static_cast<int32_t>(
       gfx::RowSizeForBufferFormat(size.width(), format, 0));
-  shared_memory.GiveToProcess(child_process, &handle.handle);
+  if (child_process == base::kNullProcessHandle)
+    handle.handle = shared_memory.TakeHandle();
+  else
+    shared_memory.GiveToProcess(child_process, &handle.handle);
   return handle;
 }
 
 // static
 std::unique_ptr<GpuMemoryBufferImplSharedMemory>
 GpuMemoryBufferImplSharedMemory::CreateFromHandle(
     const gfx::GpuMemoryBufferHandle& handle,
     const gfx::Size& size,
     gfx::BufferFormat format,
     gfx::BufferUsage usage,
@@ skipping 125 matching lines @@
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::SHARED_MEMORY_BUFFER;
   handle.id = id_;
   handle.offset = offset_;
   handle.stride = stride_;
   handle.handle = shared_memory_->handle();
   return handle;
 }
 
 }  // namespace gpu