Introduce a monotonic_clock module for Mojo.js.

mojo/mojo_apps.gypi

 {
   'targets': [
     {
       'target_name': 'mojo_js_lib',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../gpu/gpu.gyp:gles2_c_lib',
         '../gin/gin.gyp:gin',
         '../ui/gl/gl.gyp:gl',
@@ skipping 19 matching lines @@
         'apps/js/bindings/threading.cc',
         'apps/js/bindings/threading.h',
         'apps/js/bindings/core.cc',
         'apps/js/bindings/core.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/handle.cc',
         'apps/js/bindings/handle.h',
+        'apps/js/bindings/monotonic_clock.cc',
+        'apps/js/bindings/monotonic_clock.h',
         'apps/js/bindings/support.cc',
         'apps/js/bindings/support.h',
         'apps/js/bindings/waiting_callback.cc',
         'apps/js/bindings/waiting_callback.h',
       ],
     },
     {
       'target_name': 'mojo_js_unittests',
       'type': 'executable',
       'dependencies': [
@@ skipping 11 matching lines @@
       'type': 'shared_library',
       'dependencies': [
         'mojo_js_lib',
       ],
       'sources': [
         'apps/js/main.cc',
       ],
     },
   ],
 }