CrOS GMC: Update pin button tooltip text.

Bug: 1133559
Change-Id: Iae2392302136bc2032df1dca6a388566762eaadd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2439479
Commit-Queue: Jazz Xu <jazzhsu@chromium.org>
Reviewed-by: Tommy Steimel <steimel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812515}

ash/ash_strings.grd

@@ -2586,11 +2586,11 @@ This file contains the strings for ash.
       </message>
 
       <message name="IDS_ASH_GLOBAL_MEDIA_CONTROLS_PINNED_BUTTON_TOOLTIP_TEXT" desc="Tooltip for pinned button showing in global media controls' title.">
-        Unpin global media controls from shelf
+        Unpin
       </message>
 
       <message name="IDS_ASH_GLOBAL_MEDIA_CONTROLS_UNPINNED_BUTTON_TOOLTIP_TEXT" desc="Tooltip for unpinned button showing in global media controls' title.">
-        Pin global media controls to shelf
+        Pin to shelf
       </message>
 
       <!-- Power off menu  -->

ash/ash_strings_grd/IDS_ASH_GLOBAL_MEDIA_CONTROLS_PINNED_BUTTON_TOOLTIP_TEXT.png.sha1

-8c9e0930ef90d9cc07121d233d359101728f0cd7
\ No newline at end of file
+26846032c5340423260149b78cda1b109f655ac9
\ No newline at end of file

ash/ash_strings_grd/IDS_ASH_GLOBAL_MEDIA_CONTROLS_UNPINNED_BUTTON_TOOLTIP_TEXT.png.sha1

-15ecf6fae90556515bc942b81da7b7351f057a27
\ No newline at end of file
+96a4a9919160bbbe92c95a5b324e074b9c2170f2
\ No newline at end of file