GN: Add mojo_shell_tests, get more things working on android

mojo/services/public/cpp/geometry/BUILD.gn

 # Copyright 2014 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("//mojo/system.gni")
+
 component("geometry") {
   output_name = "mojo_geometry_lib"
 
   deps = [
     "//skia",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//mojo/environment:chromium",
     "//mojo/services/public/interfaces/geometry",
   ]
+  deps += mojo_system_for_component
 
   forward_dependent_configs_from = [ "//ui/gfx" ]
 
   defines = [
     "MOJO_GEOMETRY_IMPLEMENTATION",
   ]
 
   sources = [
     "lib/geometry_type_converters.cc",
     "geometry_type_converters.h",
     "mojo_geometry_export.h",
   ]
-
-  if (is_component_build) {
-    deps += [ "//mojo/system" ]
-  }
 }