add pause button for resumable in-progress downloads.

chrome/android/java/strings/android_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- android_chrome_strings.grd contains strings for Chrome for Android.
 
 FAQ:
   - How do I add, change, or remove a string?
       Just update this file.
   - Translations will happen automatically??
       Yes, indeed. Just add your string before the branch point and
       make the description good.
@@ skipping 1442 matching lines @@
       </message>
       <message name="IDS_DOWNLOAD_NOTIFICATION_COMPLETED" desc="Download notification to be displayed when a download completes.">
         Download complete.
       </message>
       <message name="IDS_DOWNLOAD_NOTIFICATION_FAILED" desc="Download notification to be displayed when a download fails.">
         Download failed.
       </message>
       <message name="IDS_DOWNLOAD_NOTIFICATION_PAUSED" desc="Download notification to be displayed when a download pauses.">
         Download paused.
       </message>
+      <message name="IDS_DOWNLOAD_NOTIFICATION_PAUSE_BUTTON" desc="Text on the button that pauses a download.">
+        Pause
+      </message>
       <message name="IDS_DOWNLOAD_NOTIFICATION_RESUME_BUTTON" desc="Text on the button that resumes a paused download.">
         Resume
       </message>
       <message name="IDS_DOWNLOAD_FAILED_REASON_FILE_ALREADY_EXISTS" desc="Message to explain that the download failed because file already exists.">
         <ph name="FILE_NAME">%1$s<ex>http://abc.com/test.pdf</ex></ph> download prevented because file already exists.
       </message>
       <message name="IDS_DOWNLOAD_FAILED_REASON_FILE_SYSTEM_ERROR" desc="Message to explain that the download failed because unknown file system error.">
         <ph name="FILE_NAME">%1$s<ex>http://abc.com/test.pdf</ex></ph> download failed due to file system errors.
       </message>
       <message name="IDS_DOWNLOAD_FAILED_REASON_INSUFFICIENT_SPACE" desc="Message to explain that the download failed because insufficient storage space.">
@@ skipping 854 matching lines @@
       </message>
       <message name="IDS_PHYSICAL_WEB_REFRESH" desc="The label for a button that initiates a scan for nearby URLs">
         Refresh
       </message>
       <message name="IDS_PHYSICAL_WEB_LAUNCH_BUTTON" desc="The label for a button that opens a list of nearby URLs">
         See what's nearby
       </message>
     </messages>
   </release>
 </grit>