Add keyboard overlay help for the Search key as a Function key extended keyboard shortcuts.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="pp_ifdef('chromeos')">. -->
 <grit-part>
   <!-- Idle Logout Dialog Strings -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog">
     Are you still there?
   </message>
   <message name="IDS_IDLE_LOGOUT_WARNING_RESTART" desc="Restart label for the idle logout dialog">
     This computer will reset in <ph name="LOGOUT_TIME_LEFT">$1<ex>20</ex></ph> seconds.
@@ skipping 2611 matching lines @@
   </message>
   <message name="IDS_KEYBOARD_OVERLAY_LEARN_MORE" desc="The text of the learn more link on the keyboard overlay.">
     Learn more
   </message>
   <message name="IDS_KEYBOARD_OVERLAY_TITLE" desc="The title of the keyboard overlay.">
     Keyboard Overlay
   </message>
   <message name="IDS_KEYBOARD_OVERLAY_INSTRUCTIONS" desc="The instructions for the keyboard overlay.">
     Hold Control, Alt, or Shift to see keyboard shortcuts for those modifiers.
   </message>
+  <message name="IDS_KEYBOARD_OVERLAY_INSTRUCTIONS_WITH_SEARCH" desc="The instructions for the keyboard overlay.">
+    Hold Control, Alt, Shift, or Search to see keyboard shortcuts for those modifiers.
+  </message>
   <message name="IDS_KEYBOARD_OVERLAY_INSTRUCTIONS_HIDE" desc="The instruction for hiding the keyboard overlay.">
     Type Ctrl+Alt+/ or Escape to hide
   </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F1" desc="The text in the keyboard overlay to explain the shortcut.">
+    F1
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F2" desc="The text in the keyboard overlay to explain the shortcut.">
+    F2
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F3" desc="The text in the keyboard overlay to explain the shortcut.">
+    F3
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F4" desc="The text in the keyboard overlay to explain the shortcut.">
+    F4
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F5" desc="The text in the keyboard overlay to explain the shortcut.">
+    F5
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F6" desc="The text in the keyboard overlay to explain the shortcut.">
+    F6
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F7" desc="The text in the keyboard overlay to explain the shortcut.">
+    F7
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F8" desc="The text in the keyboard overlay to explain the shortcut.">
+    F8
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F9" desc="The text in the keyboard overlay to explain the shortcut.">
+    F9
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F10" desc="The text in the keyboard overlay to explain the shortcut.">
+    F10
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F11" desc="The text in the keyboard overlay to explain the shortcut.">
+    F11
+  </message>
+  <message name="IDS_KEYBOARD_OVERLAY_F12" desc="The text in the keyboard overlay to explain the shortcut.">
+    F12
+  </message>
   <!-- BEGIN GENERATED KEYBOARD OVERLAY STRINGS -->
   <message name="IDS_KEYBOARD_OVERLAY_ACTIVATE_LAST_LAUNCHER_ITEM" desc="The text in the keyboard overlay to explain the shortcut (Open the last launcher item).">
     Activate last launcher item
   </message>
   <message name="IDS_KEYBOARD_OVERLAY_ACTIVATE_LAST_TAB" desc="The text in the keyboard overlay to explain the shortcut.">
     Activate last tab
   </message>
   <message name="IDS_KEYBOARD_OVERLAY_ACTIVATE_LAUNCHER_ITEM_1" desc="The text in the keyboard overlay to explain the shortcut (Open the launcher item at the specified position).">
     Activate launcher item 1
   </message>
@@ skipping 803 matching lines @@
   <message name="IDS_LOGIN_MANAGED_BY_STATUS_NETWORK_ERROR" desc="Text for the network error status in 'Managed by DOMAIN' label on login screen.">
     Network error while communicating with the device management service.
   </message>
   <message name="IDS_LOGIN_MANAGED_BY_NOTICE" desc="Text for the notification bar on the login screen showing that this is a managed device.">
     This device is managed by <ph name="DOMAIN">$1<ex>yourdomain.com</ex></ph>.
   </message>
   <message name="IDS_LOGIN_MANAGED_REPORTING_HINT" desc="Text for the hint on reporting features displayed in the enterprise notification bar on the login screen.">
     Device usage may be tracked.
   </message>
 </grit-part>