Fix grammar of popup-blocker notification on Android.

Bug: 731328
Change-Id: I61198120338e162c29dfbc582ea7b25063afb6bc
Reviewed-on: https://chromium-review.googlesource.com/775897Reviewed-by: Lucas Garron <lgarron@chromium.org>
Commit-Queue: Nathan Parker <nparker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517262}

chrome/app/generated_resources.grd

@@ -5762,7 +5762,7 @@ I don't think this site should be blocked!
           Always show
         </message>
         <message name="IDS_POPUPS_BLOCKED_INFOBAR_TEXT" desc="Pop-up Blocking Title [CHAR-LIMIT=32] [ICU Syntax]">
-          {NUM_POPUPS,plural,=1{A pop-up is blocked} other{# pop-ups are blocked}}
+          {NUM_POPUPS,plural,=1{Pop-up blocked} other{# pop-ups blocked}}
         </message>
       </if>
       <message name="IDS_PDF_TAB_LABEL" desc="Label for the pdf plugin tab on Content Settings dialog">