arc: remove top from system processes and add new service state

Make the process with state TOP appear as a regular app in the task
scheduler instead of as a system process. This also allows users to kill
it from the task scheduler. Have the new process state
TRANSIENT_BACKGROUND appear as a service.

Bug: none
Test: Ensure TOP app is a regular app in the task scheduler.
Change-Id: I49efca2bd2848479f6b590588fd357393d8a591d
Reviewed-on: https://chromium-review.googlesource.com/1097975Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Christopher Morin <cmtm@google.com>
Cr-Commit-Position: refs/heads/master@{#569350}

chrome/browser/task_manager/providers/arc/arc_process_task.cc

@@ -39,14 +39,14 @@ base::string16 MakeTitle(const arc::ArcProcess& arc_process) {
   switch (arc_process.process_state()) {
     case arc::mojom::ProcessState::PERSISTENT:
     case arc::mojom::ProcessState::PERSISTENT_UI:
-    case arc::mojom::ProcessState::TOP:
       name_template = IDS_TASK_MANAGER_ARC_SYSTEM;
       break;
-    case arc::mojom::ProcessState::BOUND_FOREGROUND_SERVICE:
     case arc::mojom::ProcessState::FOREGROUND_SERVICE:
-    case arc::mojom::ProcessState::SERVICE:
+    case arc::mojom::ProcessState::BOUND_FOREGROUND_SERVICE:
     case arc::mojom::ProcessState::IMPORTANT_FOREGROUND:
     case arc::mojom::ProcessState::IMPORTANT_BACKGROUND:
+    case arc::mojom::ProcessState::TRANSIENT_BACKGROUND:
+    case arc::mojom::ProcessState::SERVICE:
       name_template = IDS_TASK_MANAGER_ARC_PREFIX_BACKGROUND_SERVICE;
       break;
     case arc::mojom::ProcessState::RECEIVER: