Cleanup GN BUILD files, gni's and imports.

mandoline/tab/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//testing/test.gni")
-import("//third_party/mojo/src/mojo/public/mojo_application.gni")
-import("//third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
+import("//mojo/public/mojo_application.gni")
 
 source_set("tab") {
   sources = [
     "frame.cc",
     "frame.h",
     "frame_services.cc",
     "frame_services.h",
     "frame_tree.cc",
     "frame_tree.h",
     "frame_tree_delegate.h",
@@ skipping 24 matching lines @@
     "//components/view_manager/public/cpp",
     "//components/view_manager/public/interfaces",
     "//mandoline/tab/public/interfaces",
     "//mojo/application/public/cpp:test_support",
     "//ui/mojo/geometry:interfaces",
     "//ui/mojo/geometry:util",
   ]
 
   data_deps = [ "//components/view_manager" ]
 }