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 "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_observer.h"
+#include "content/browser/renderer_host/offscreen_canvas_surface_impl.h"
+
+namespace content {
+
+class CONTENT_EXPORT OffscreenCanvasSurfaceManager
+    : public cc::SurfaceObserver {
+ public:
+  OffscreenCanvasSurfaceManager();
+  virtual ~OffscreenCanvasSurfaceManager();
+
+  static OffscreenCanvasSurfaceManager* GetInstance();
+
+  void RegisterOffscreenCanvasSurfaceInstance(cc::FrameSinkId,
+                                              OffscreenCanvasSurfaceImpl*);
+  void UnregisterOffscreenCanvasSurfaceInstance(cc::FrameSinkId);
+  OffscreenCanvasSurfaceImpl* GetSurfaceInstance(cc::FrameSinkId);
+
+ private:
+  friend class OffscreenCanvasSurfaceManagerTest;
+
+  // cc::SurfaceObserver implementation.
+  // TODO(crbug.com/662498): Implement these functions when
+  // OffscreenCanvasSurfaceManager must propagate the resizing information
+  // back to renderer/main.
+  void OnSurfaceCreated(const cc::SurfaceId& surface_id,
+                        const gfx::Size& frame_size,
+                        float device_scale_factor) override {}
+  void OnSurfaceDamaged(const cc::SurfaceId&, bool* changed) override {}
+
+  // When an OffscreenCanvasSurfaceImpl instance is destructed, it will
+  // unregister the corresponding entry from this map.
+  std::unordered_map<cc::FrameSinkId,
+                     OffscreenCanvasSurfaceImpl*,
+                     cc::FrameSinkIdHash>
+      registered_surface_instances_;
+  DISALLOW_COPY_AND_ASSIGN(OffscreenCanvasSurfaceManager);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_OFFSCREEN_CANVAS_SURFACE_MANAGER_H_