Experimental 'purging and suspending' backgrounded tabs behind the flag

content/renderer/render_thread_impl.h

 // Copyright (c) 2012 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_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 445 matching lines @@
   RenderThreadImpl(std::unique_ptr<base::MessageLoop> main_message_loop,
                    std::unique_ptr<scheduler::RendererScheduler> scheduler);
 
  private:
   // IPC::Listener
   void OnChannelError() override;
 
   // ChildThread
   bool OnControlMessageReceived(const IPC::Message& msg) override;
   void OnProcessBackgrounded(bool backgrounded) override;
+  void OnProcessPurgeAndSuspend() override;
   void RecordAction(const base::UserMetricsAction& action) override;
   void RecordComputedAction(const std::string& action) override;
 
   // GpuChannelHostFactory implementation:
   bool IsMainThread() override;
   scoped_refptr<base::SingleThreadTaskRunner> GetIOThreadTaskRunner() override;
   std::unique_ptr<base::SharedMemory> AllocateSharedMemory(
       size_t size) override;
 
   void Init(scoped_refptr<base::SingleThreadTaskRunner>& resource_task_queue);
@@ skipping 216 matching lines @@
     shell::mojom::InterfaceProviderRequest services_;
     shell::mojom::InterfaceProviderPtr exposed_services_;
   };
 
   typedef std::map<int, scoped_refptr<PendingRenderFrameConnect>>
       PendingRenderFrameConnectMap;
   PendingRenderFrameConnectMap pending_render_frame_connects_;
 
   mojom::StoragePartitionServicePtr storage_partition_service_;
 
+  bool is_backgrounded_;
+  bool is_cache_purged_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_