Use loadable module instead of shared library.

mojo/mojo_apps.gypi

 {
   'targets': [
     {
       'target_name': 'mojo_js_lib',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../gin/gin.gyp:gin',
         '../ui/gl/gl.gyp:gl',
         '../v8/tools/gyp/v8.gyp:v8',
@@ skipping 51 matching lines @@
         'mojo_run_all_unittests',
         'mojo_public_test_interfaces',
       ],
       'sources': [
         'apps/js/test/js_to_cpp_unittest.cc',
         'apps/js/test/run_apps_js_tests.cc',
       ],
     },
     {
       'target_name': 'mojo_js',
-      'type': 'shared_library',
+      'type': 'loadable_module',
       'dependencies': [
         'mojo_js_lib',
         'mojo_system_impl',
       ],
       'sources': [
         'apps/js/main.cc',
       ],
     },
   ],
   'conditions': [
@@ skipping 10 matching lines @@
             'mojo_apps_js_unittests.isolate',
           ],
           'sources': [
             'mojo_apps_js_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }