Experimental 'purging and suspending' backgrounded tabs behind the flag

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 806d32bfbd261725bf64de15bf2db7ae1358d6c4..088397b17b83230bf24967b45e7f294d7a07a22e 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -463,6 +463,7 @@ class CONTENT_EXPORT RenderThreadImpl
   // 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;
 
@@ -699,6 +700,9 @@ class CONTENT_EXPORT RenderThreadImpl
 
   mojom::StoragePartitionServicePtr storage_partition_service_;
 
+  bool is_backgrounded_;
+  bool is_cache_purged_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };