Remove the deprecated Alt+Shift shortcut completely

ash/ash_chromeos_strings.grdp

Index: ash/ash_chromeos_strings.grdp
diff --git a/ash/ash_chromeos_strings.grdp b/ash/ash_chromeos_strings.grdp
index 23b56cac9face20767ff7f28bbd0db1ea4678153..0836b42f1a512d60c75b644f25252ae49f3cb492 100644
--- a/ash/ash_chromeos_strings.grdp
+++ b/ash/ash_chromeos_strings.grdp
@@ -612,12 +612,6 @@ Press Shift + Alt to switch.
   <message name="IDS_SHORTCUT_TASK_MANAGER_NEW" desc="the new shortcut to open the task manager.">
     Search+Esc
   </message>
-  <message name="IDS_SHORTCUT_NEXT_IME_OLD" desc="the old deprecated shortcut to switch to the next input method.">
-    Shift+Alt
-  </message>
-  <message name="IDS_SHORTCUT_NEXT_IME_NEW" desc="the new shortcut to switch to the next input method.">
-    Ctrl+Shift+Space
-  </message>
   <message name="IDS_DEPRECATED_LOCK_SCREEN_MSG"
            desc="Notification message to tell users about the deprecation of Ctrl+Shift+L shortcut to lock the screen.">
     The shortcut to lock the screen has changed. Please use <ph name="NEW_SHORTCUT">$1<ex>Search+L</ex></ph> instead of <ph name="OLD_SHORTCUT">$2<ex>Ctrl+Shift+L</ex></ph>.
@@ -626,10 +620,6 @@ Press Shift + Alt to switch.
            desc="Notification message to tell users about the deprecation of Shift+ESC shortcut to show the task manager.">
     The shortcut to open the task manager has changed. Please use <ph name="NEW_SHORTCUT">$1<ex>Search+Esc</ex></ph> instead of <ph name="OLD_SHORTCUT">$2<ex>Shift+Esc</ex></ph>.
   </message>
-  <message name="IDS_DEPRECATED_NEXT_IME_MSG"
-           desc="Notification message to tell users about the deprecation of Shift+Alt shortcut to switch to the next input method.">
-    The shortcut to switch to the next input method has changed. Please use <ph name="NEW_SHORTCUT">$1<ex>Ctrl+Shift+Space</ex></ph> instead of <ph name="OLD_SHORTCUT">$2<ex>Shift+Alt</ex></ph>.
-  </message>
 
   <!-- Notification that an accelerator was pressed, so the user knows how to toggle it back -->
   <message name="IDS_HIGH_CONTRAST_ACCEL_MSG"