Use a check item instead of changing its text.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
===================================================================
--- chrome/app/generated_resources.grd	(revision 124915)
+++ chrome/app/generated_resources.grd	(working copy)
@@ -500,9 +500,6 @@
         <message name="IDS_CONTENT_CONTEXT_SPELLING_BUBBLE_DISABLE" desc="The button text that disallows integrating the spelling service of Google.">
           No thanks
         </message>
-        <message name="IDS_CONTENT_CONTEXT_SPELLING_STOP_ASKING_GOOGLE" desc="The context-menu item that stops integrating the spelling service.">
-          Stop asking Google for suggestions
-        </message>
         <message name="IDS_CONTENT_CONTEXT_SPELLING_CHECKING" desc="The place-holder message shown while the Spelling service is checking text">
           Loading suggestion
         </message>
@@ -709,9 +706,6 @@
         <message name="IDS_CONTENT_CONTEXT_SPELLING_BUBBLE_DISABLE" desc="In Title Case: The button text that disallows integrating the spelling service of Google.">
           No Thanks
         </message>
-        <message name="IDS_CONTENT_CONTEXT_SPELLING_STOP_ASKING_GOOGLE" desc="The context-menu item that stops integrating the spelling service.">
-          Stop asking Google for suggestions
-        </message>
         <message name="IDS_CONTENT_CONTEXT_SPELLING_CHECKING" desc="The place-holder message shown while the Spelling service is checking text">
           Loading suggestion
         </message>