Move existing Mojo JS <--> CPP tests out of webui test harness.

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 19 matching lines @@
         'apps/js/bindings/threading.h',
         'apps/js/bindings/gl/context.cc',
         'apps/js/bindings/gl/context.h',
         'apps/js/bindings/gl/module.cc',
         'apps/js/bindings/gl/module.h',
         'apps/js/bindings/monotonic_clock.cc',
         'apps/js/bindings/monotonic_clock.h',
       ],
     },
     {
+      'target_name': 'mojo_apps_js_bindings',
+      'type': 'static_library',
+      'sources': [
+        'apps/js/test/js_to_cpp.mojom',
+      ],
+      'variables': {
+        'mojom_base_output_dir': 'mojo',
+      },
+      'includes': [ 'public/tools/bindings/mojom_bindings_generator.gypi' ],
+      'export_dependent_settings': [
+        'mojo_cpp_bindings',
+      ],
+      'dependencies': [
+        'mojo_cpp_bindings',
+      ],
+    },
+    {
       'target_name': 'mojo_apps_js_unittests',
       'type': 'executable',
       'dependencies': [
         '../gin/gin.gyp:gin_test',
+        'mojo_apps_js_bindings',
         'mojo_common_lib',
         'mojo_common_test_support',
         'mojo_js_lib',
         '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',
       ],
@@ skipping 24 matching lines @@
             'mojo_apps_js_unittests.isolate',
           ],
           'sources': [
             'mojo_apps_js_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }