Create manager to track OffscreenCanvasSurfaceImpl instances

content/browser/renderer_host/offscreen_canvas_surface_manager.h

+// 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.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_OFFSCREEN_CANVAS_SURFACE_MANAGER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_OFFSCREEN_CANVAS_SURFACE_MANAGER_H_
+
+#include "base/memory/weak_ptr.h"
+#include "content/browser/renderer_host/offscreen_canvas_compositor_frame_sink.h"
+#include "content/browser/renderer_host/offscreen_canvas_surface_impl.h"
+
+namespace content {
+
+class OffscreenCanvasSurfaceManager {
+ public:
+  OffscreenCanvasSurfaceManager();
+  ~OffscreenCanvasSurfaceManager();
+
+  // OffscreenCanvasSurfaceManager is lazily created only when it is needed.
+  static OffscreenCanvasSurfaceManager* GetInstance();
+  static void Terminate();
+
+  void RegisterOffscreenCanvasSurfaceInstance(int canvas_id,
+                                              OffscreenCanvasSurfaceImpl*);
+  void UnregisterOffscreenCanvasSurfaceInstance(int canvas_id);
+
+  void RegisterCompositorFrameSinkInstance(int canvas_id,
+                                           OffscreenCanvasCompositorFrameSink*);
+  void UnregisterCompositorFrameSinkInstance(int canvas_id);
+
+ private:
+  std::unordered_map<int, base::WeakPtr<OffscreenCanvasSurfaceImpl>>
+      registered_surface_instances_;
+  std::unordered_map<int, base::WeakPtr<OffscreenCanvasCompositorFrameSink>>
+      registered_compositor_frame_sink_instances_;
+  DISALLOW_COPY_AND_ASSIGN(OffscreenCanvasSurfaceManager);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_OFFSCREEN_CANVAS_SURFACE_MANAGER_H_