GMC: Add picture-in-picture button to zenith dialog.

This CL adds picture-in-picture button to zenith dialog.
Will follow up with integration tests and unit tests.

Bug: 1047314
Change-Id: Id435d557b2eb80ac8d262da7f137a72b1cc1908c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2030353
Reviewed-by: Tommy Steimel <[email protected]>
Reviewed-by: Evan Stade <[email protected]>
Reviewed-by: Becca Hughes <[email protected]>
Commit-Queue: Jazz Xu <[email protected]>
Commit-Queue: Becca Hughes <[email protected]>
Cr-Commit-Position: refs/heads/master@{#737098}
diff --git a/components/media_message_center_strings.grdp b/components/media_message_center_strings.grdp
index ac1c51e..d525de6 100644
--- a/components/media_message_center_strings.grdp
+++ b/components/media_message_center_strings.grdp
@@ -18,6 +18,12 @@
   <message name="IDS_MEDIA_MESSAGE_CENTER_MEDIA_NOTIFICATION_ACTION_NEXT_TRACK" desc="The button to trigger media playback to go to the next track.">
     Next Track
   </message>
+  <message name="IDS_MEDIA_MESSAGE_CENTER_MEDIA_NOTIFICATION_ACTION_ENTER_PIP" desc="The button to trigeer media playback to go in pip mode.">
+    Enter picture-in-picture
+  </message>
+  <message name="IDS_MEDIA_MESSAGE_CENTER_MEDIA_NOTIFICATION_ACTION_EXIT_PIP" desc="The button to trigeer media playback to exit pip mode.">
+    Exit picture-in-picture
+  </message>
   <message name="IDS_MEDIA_MESSAGE_CENTER_MEDIA_NOTIFICATION_ACCESSIBLE_NAME" desc="The accessible name for the media notification to control playback.">
     Media Controls
   </message>