Add managed user lock/unlock button for the extensions page.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index e0ba189b67147846d91e93adb7508fdfc4b65fdf..b9e111c1c4fb8b2ea53031ff46d5003f5e21b700 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5460,6 +5460,12 @@ Public Exponent (<ph name="PUBLIC_EXPONENT_NUM_BITS">$3<ex>24</ex></ph> bits):
       <message name="IDS_EXTENSIONS_RESTART" desc="The link for restarting apps.">
         Restart
       </message>
+      <message name="IDS_EXTENSIONS_LOCK_BUTTON" desc="The button to lock the extensions for a managed user.">
+        Lock
+      </message>
+      <message name="IDS_EXTENSIONS_UNLOCK_BUTTON" desc="The button to unlock the extensions for a managed user.">
+        Unlock
+      </message>
       <if expr="is_macosx">
         <message name="IDS_EXTENSIONS_RELOAD_UNPACKED" desc="The link for reloading unpacked extensions.">
           Reload (⌘R)