Add a simple compositor for Sky

sky/compositor/surface_allocator.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 "sky/compositor/surface_allocator.h"
+
+#include "base/logging.h"
+
+namespace sky {
+
+SurfaceAllocator::SurfaceAllocator(uint32_t id_namespace)
+    : id_namespace_(id_namespace), next_id_(1) {
+  DCHECK(id_namespace);
+}
+
+SurfaceAllocator::~SurfaceAllocator() {
+}
+
+uint64_t SurfaceAllocator::CreateSurfaceId() {
+  return static_cast<uint64_t>(id_namespace_) << 32 | next_id_++;

[eseidel, 2014/11/20 20:40:32]

Could you explain to the next person what the heck you're trying to do here.

[ojan, 2014/11/20 21:25:46]

+1

[abarth-chromium, 2014/11/20 22:07:20]

Done.

+}
+
+}  // namespace sky