Update chrome://media-app-guest paths for CIPD -> GIT migration.

https://crbug.com/1005726 requires us to use a GIT repo to host compiled
assets rather than a CIPD package. The CIPD is installed to a subfolder
of that GIT repo, so update the .grdp paths to point at this subfolder
instead of the repo root.

https://crrev.com/i/1835288 adds the DEPS change.

Tested with MediaAppUIBrowserTest.GuestCanLoad and enable_cros_media_app = true.

Bug: 996088
Change-Id: I2ab0395ed5b76faa47c23273d903d8dc68bf1761
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1824301Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699579}

chromeos/resources/media_app_resources.grdp

@@ -9,13 +9,13 @@
   <if expr="enable_cros_media_app">
     <then>
       <include name="IDR_MEDIA_APP_APP_JS"
-          file="../components/media_app_ui/resources/app/js/app_main.js"
+          file="../components/media_app_ui/resources/app/app/js/app_main.js"
           type="BINDATA" />
       <include name="IDR_MEDIA_APP_IMAGE_HANDLER_MODULE_JS"
-          file="../components/media_app_ui/resources/app/js/app_image_handler_module.js"
+          file="../components/media_app_ui/resources/app/app/js/app_image_handler_module.js"
           type="BINDATA" />
       <include name="IDR_MEDIA_APP_DROP_TARGET_MODULE_JS"
-          file="../components/media_app_ui/resources/app/js/app_drop_target_module.js"
+          file="../components/media_app_ui/resources/app/app/js/app_drop_target_module.js"
           type="BINDATA" />
     </then>
     <else>