app_list: move presenter to ash.

Since presenter belongs to UI, let's move it to Ash at this moment,
so that future CLs will be smaller.

Bug: 733662
Change-Id: I30809e34bb96406516fcdcefb27e29a440634bf9
Reviewed-on: https://chromium-review.googlesource.com/953092
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Jiaquan He <hejq@google.com>
Cr-Commit-Position: refs/heads/master@{#541654}

diff --git a/BUILD.gn b/BUILD.gn
index 5a125a1..45f69298 100644
--- a/BUILD.gn
+++ b/BUILD.gn

@@ -370,13 +370,13 @@
       "//ash:ash_content_unittests",
       "//ash:ash_shell_with_content",
       "//ash:ash_unittests",
+      "//ash/app_list/presenter:app_list_presenter_unittests",
       "//chromeos:chromeos_unittests",
       "//chromeos/components:chromeos_components_unittests",
       "//chromeos/services:chromeos_services_unittests",
       "//components/session_manager/core",
       "//ui/app_list:app_list_demo",
       "//ui/app_list:app_list_unittests",
-      "//ui/app_list/presenter:app_list_presenter_unittests",
       "//ui/arc:ui_arc_unittests",
       "//ui/chromeos:ui_chromeos_unittests",
     ]