[Mojo Video Capture] Adapt video_capture service to refactored video capture stack

media/capture/video/shared_memory_buffer_handle.cc

+// Copyright 2016 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 "media/capture/video/shared_memory_buffer_handle.h"
+
+#include "base/memory/ptr_util.h"
+#include "mojo/public/cpp/system/platform_handle.h"
+
+namespace media {
+
+SharedMemoryBufferHandle::SharedMemoryBufferHandle(
+    base::SharedMemory* shared_memory,
+    size_t mapped_size)
+    : shared_memory_(shared_memory), mapped_size_(mapped_size) {}
+
+SharedMemoryBufferHandle::~SharedMemoryBufferHandle() = default;
+
+size_t SharedMemoryBufferHandle::mapped_size() const {
+  return mapped_size_;
+}
+
+uint8_t* SharedMemoryBufferHandle::data() const {
+  return static_cast<uint8_t*>(shared_memory_->memory());
+}
+
+const uint8_t* SharedMemoryBufferHandle::const_data() const {
+  return static_cast<const uint8_t*>(shared_memory_->memory());
+}
+
+}  // namespace media