gpu: Add IOSurface backed GpuMemoryBuffer implementation.

content/common/gpu/client/gpu_memory_buffer_impl_shm.cc

+// Copyright 2013 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/common/gpu/client/gpu_memory_buffer_impl_shm.h"
+
+#include "base/logging.h"
+
+namespace content {
+
+GpuMemoryBufferImplShm::GpuMemoryBufferImplShm(
+    gfx::Size size, unsigned internalformat)
+    : GpuMemoryBufferImpl(size, internalformat) {
+}
+
+GpuMemoryBufferImplShm::~GpuMemoryBufferImplShm() {
+}
+
+bool GpuMemoryBufferImplShm::Initialize(gfx::GpuMemoryBufferHandle handle) {
+  if (!base::SharedMemory::IsHandleValid(handle.handle))
+    return false;
+  shared_memory_.reset(new base::SharedMemory(handle.handle, false));
+  DCHECK(!shared_memory_->memory());
+  return true;
+}
+
+bool GpuMemoryBufferImplShm::InitializeFromSharedMemory(
+    scoped_ptr<base::SharedMemory> shared_memory) {
+  shared_memory_ = shared_memory.Pass();
+  DCHECK(!shared_memory_->memory());
+  return true;
+}
+
+void GpuMemoryBufferImplShm::Map(AccessMode mode, void** vaddr) {
+  DCHECK(!mapped_);
+  *vaddr = NULL;
+  if (!shared_memory_->Map(size_.GetArea() * BytesPerPixel(internalformat_)))
+    return;
+  *vaddr = shared_memory_->memory();
+  mapped_ = true;
+}
+
+void GpuMemoryBufferImplShm::Unmap() {
+  DCHECK(mapped_);
+  shared_memory_->Unmap();
+  mapped_ = false;
+}
+
+gfx::GpuMemoryBufferHandle GpuMemoryBufferImplShm::GetHandle() const {
+  gfx::GpuMemoryBufferHandle handle;
+  handle.type = gfx::SHARED_MEMORY_BUFFER;
+  handle.handle = shared_memory_->handle();
+  return handle;
+}
+
+}  // namespace content