Add multi-process GpuMemoryBuffer framework.

content/common/gpu/client/gpu_memory_buffer_impl.cc

+// Copyright (c) 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.h"
+
+#include "ui/gl/gl_bindings.h"
+
+namespace content {
+
+GpuMemoryBufferImpl::GpuMemoryBufferImpl(
+    scoped_ptr<base::SharedMemory> shared_memory,
+    size_t width,
+    size_t height,
+    unsigned internalformat)
+    : shared_memory_(shared_memory.Pass()),
+      size_(gfx::Size(width, height)),
+      internalformat_(internalformat),
+      mapped_(false) {
+  DCHECK(!shared_memory_->memory());
+  DCHECK(IsFormatValid(internalformat));
+}
+
+GpuMemoryBufferImpl::~GpuMemoryBufferImpl() {
+}
+
+void GpuMemoryBufferImpl::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 GpuMemoryBufferImpl::Unmap() {
+  DCHECK(mapped_);
+  shared_memory_->Unmap();
+  mapped_ = false;
+}
+
+bool GpuMemoryBufferImpl::IsMapped() const {
+  return mapped_;
+}
+
+uint32 GpuMemoryBufferImpl::GetStride() const {
+  return size_.width() * BytesPerPixel(internalformat_);
+}
+
+gfx::GpuMemoryBufferHandle GpuMemoryBufferImpl::GetHandle() const {
+  gfx::GpuMemoryBufferHandle handle;
+  handle.type = gfx::SHARED_MEMORY_BUFFER;
+  handle.handle = shared_memory_->handle();
+  return handle;
+}
+
+// static
+bool GpuMemoryBufferImpl::IsFormatValid(unsigned internalformat) {
+  // GL_RGBA8_OES is the only supported format at the moment.
+  switch (internalformat) {
+    case GL_RGBA8_OES:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// static
+size_t GpuMemoryBufferImpl::BytesPerPixel(unsigned internalformat) {
+  // GL_RGBA_OES has 4 bytes per pixel.
+  switch (internalformat) {
+    case GL_RGBA8_OES:
+      return 4;
+    default:
+      NOTREACHED();
+      return 0;
+  }
+}
+
+}  // namespace content