Add a Javascript closure compiler target for VrShell.

BUG=
TEST=Ran third_party/closure_compiler/run_compiler vr_shell_ui

Review-Url: https://codereview.chromium.org/2617173002
Cr-Commit-Position: refs/heads/master@{#442001}

third_party/closure_compiler/compiled_resources2.gyp

@@ -30,6 +30,7 @@
         '<(DEPTH)/chrome/browser/resources/offline_pages/compiled_resources2.gyp:*',
         '<(DEPTH)/chrome/browser/resources/settings/compiled_resources2.gyp:*',
         '<(DEPTH)/chrome/browser/resources/uber/compiled_resources2.gyp:*',
+        '<(DEPTH)/chrome/browser/resources/vr_shell/compiled_resources2.gyp:*',
         '<(DEPTH)/ui/file_manager/compiled_resources2.gyp:*',
         '<(DEPTH)/ui/webui/resources/cr_elements/compiled_resources2.gyp:*',
         '<(DEPTH)/ui/webui/resources/js/chromeos/compiled_resources2.gyp:*',