Add Browser Task Scheduler Flags to iOS

ios/chrome/app/strings/ios_strings.grd

Index: ios/chrome/app/strings/ios_strings.grd
diff --git a/ios/chrome/app/strings/ios_strings.grd b/ios/chrome/app/strings/ios_strings.grd
index a96923eff67ddbcc7611aecbae94b7ebdf7ffa38..ed74c59951a0566f9140042a3a55d2f0b86bc311 100644
--- a/ios/chrome/app/strings/ios_strings.grd
+++ b/ios/chrome/app/strings/ios_strings.grd
@@ -262,6 +262,18 @@ brand. [Length: 70em]">
         http://www.google.com/intl/[GRITLANGCODE]/chrome/browser/privacy/
       </message>
 
+      <!-- Browser Task Scheduler -->
+      <message name="IDS_FLAGS_BROWSER_TASK_SCHEDULER_NAME"

[rohitrao (ping after 24h), 2016/10/25 12:07:07]

Could you name these IDS_IOS_FLAGS_, for consistency with the other names in
this file?

[robliao, 2016/10/26 17:28:19]

Done.

+               desc="Name of about:flag option to control the availability of the browser task scheduler."
+               translateable="false">
+        Browser Task Scheduler
+      </message>
+      <message name="IDS_FLAGS_BROWSER_TASK_SCHEDULER_DESCRIPTION"
+               desc="Description of about:flag option to control the availability of the browser task scheduler."
+               translateable="false">
+        Enables the browser task scheduler to dispatch tasks instead of the existing worker pools. The browser task scheduler will only be used if variation parameters are available.
+      </message>
+
     </messages>
   </release>
 </grit>