Aura/ÜC: Drop frames on background tabs

content/browser/renderer_host/delegated_frame_evictor.h

+// 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.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_DELEGATED_FRAME_EVICTOR_H_
+#define CONTENT_BROWSER_RENDERER_HOST_DELEGATED_FRAME_EVICTOR_H_
+
+#include "content/browser/renderer_host/renderer_frame_manager.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class CONTENT_EXPORT DelegatedFrameEvictorClient {
+ public:
+  virtual ~DelegatedFrameEvictorClient() {}
+  virtual void EvictDelegatedFrame() = 0;
+};
+
+class CONTENT_EXPORT DelegatedFrameEvictor : public RendererFrameManagerClient {
+ public:
+  // |client| must outlive |this|.
+  explicit DelegatedFrameEvictor(DelegatedFrameEvictorClient* client);
+  virtual ~DelegatedFrameEvictor();
+
+  void SwappedFrame(bool visible);
+  void DiscardedFrame();
+  void SetVisible(bool visible);
+
+ private:
+  // RendererFrameManagerClient implementation.
+  virtual void EvictCurrentFrame() OVERRIDE;
+
+  DelegatedFrameEvictorClient* client_;
+  bool has_frame_;
+
+  DISALLOW_COPY_AND_ASSIGN(DelegatedFrameEvictor);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_DELEGATED_FRAME_EVICTOR_H_