[DevTools] (Re-)introduce SDK.Target.Type

We failed to abstract away the types with capabilities, so
I am bringing the type back in preparation of removing
service/shadow workers shadow page target.

Bug: 882467
Change-Id: I480bb18b1cfa9cf79e83435d735d102711991562
Reviewed-on: https://chromium-review.googlesource.com/c/1310759
Reviewed-by: Joel Einbinder <[email protected]>
Commit-Queue: Dmitry Gozman <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#604446}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 1382cbcc0e916f8449d471dd54ca62aeb14db252
diff --git a/front_end/main/Main.js b/front_end/main/Main.js
index 518fb19..0eb31b1 100644
--- a/front_end/main/Main.js
+++ b/front_end/main/Main.js
@@ -561,7 +561,7 @@
     }
 
     if (Components.dockController.dockSide() === Components.DockController.State.Undocked &&
-        SDK.targetManager.mainTarget() && SDK.targetManager.mainTarget().hasBrowserCapability())
+        SDK.targetManager.mainTarget() && SDK.targetManager.mainTarget().type() === SDK.Target.Type.Frame)
       contextMenu.defaultSection().appendAction('inspector_main.focus-debuggee', Common.UIString('Focus debuggee'));
 
     contextMenu.defaultSection().appendAction(