DevTools: return remote debugging targets sorted by last active time (as it was long ago).

content/public/browser/devtools_external_agent_proxy_delegate.h

Index: content/public/browser/devtools_external_agent_proxy_delegate.h
diff --git a/content/public/browser/devtools_external_agent_proxy_delegate.h b/content/public/browser/devtools_external_agent_proxy_delegate.h
index 56f44715922cdabbd46ffa0848cfecf246a71dd5..137a7db13f50c9576b23bbe35231b3048aa17bac 100644
--- a/content/public/browser/devtools_external_agent_proxy_delegate.h
+++ b/content/public/browser/devtools_external_agent_proxy_delegate.h
@@ -51,6 +51,9 @@ class DevToolsExternalAgentProxyDelegate {
   // Reloads agent host.
   virtual bool Close() = 0;
 
+  // Returns the time when the host was last active.
+  virtual base::TimeTicks GetLastActivityTime() = 0;
+
   // Sends a message to the agent.
   virtual void SendMessageToBackend(const std::string& message) = 0;
 };