Add hovering feature to AshDevToolsDOMAgent

components/ui_devtools/devtools_server.h

Index: components/ui_devtools/devtools_server.h
diff --git a/components/ui_devtools/devtools_server.h b/components/ui_devtools/devtools_server.h
index 73a8ae411d1b9bdb8ffef46bdd046c86edca96fb..3f6ca85ba656f1fd349e96f348d48a1d863ec8c0 100644
--- a/components/ui_devtools/devtools_server.h
+++ b/components/ui_devtools/devtools_server.h
@@ -28,7 +28,7 @@ class UI_DEVTOOLS_EXPORT UiDevToolsServer
   // Returns an empty unique_ptr if ui devtools flag isn't enabled or if a
   // server instance has already been created.
   static std::unique_ptr<UiDevToolsServer> Create(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
+      scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner);
 
   // Returns a list of attached UiDevToolsClient name + URL
   using NameUrlPair = std::pair<std::string, std::string>;
@@ -39,7 +39,7 @@ class UI_DEVTOOLS_EXPORT UiDevToolsServer
 
  private:
   explicit UiDevToolsServer(
-      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
+      scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner);
 
   void Start(const std::string& address_string, uint16_t port);
   void StartServer(const std::string& address_string, uint16_t port);
@@ -60,7 +60,8 @@ class UI_DEVTOOLS_EXPORT UiDevToolsServer
 
   std::unique_ptr<base::Thread> thread_;
   std::unique_ptr<net::HttpServer> server_;
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
 
   // The server (owned by ash for now)
   static UiDevToolsServer* devtools_server_;