Revert of Allow headless TabSocket in isolated worlds & remove obsolete logic

headless/test/headless_browser_test.h

Index: headless/test/headless_browser_test.h
diff --git a/headless/test/headless_browser_test.h b/headless/test/headless_browser_test.h
index 1e3bc1674432f8901a10e7958ae4f3a42e5ffa3a..e5e29e5f214f3d2c9bf43455efed183a4528d2e8 100644
--- a/headless/test/headless_browser_test.h
+++ b/headless/test/headless_browser_test.h
@@ -120,12 +120,8 @@
   // the map returned is empty.
   virtual ProtocolHandlerMap GetProtocolHandlers();
 
-  // The TabSocket type to request when creating |web_contents_|.
-  virtual HeadlessWebContents::Builder::TabSocketType GetTabSocketType();
-
-  // Selects between creating the TabSocket only in an isolated world or the
-  // main world.
-  virtual bool GetCreateTabSocketOnlyForIsolatedWorld();
+  // Whether or not we should request a TabSocket when creating |web_contents_|.
+  virtual bool GetCreateTabSocket();
 
  protected:
   void RunTest();