[Translate] Keep infobar when toggling setting in TranslateInfoBarDelegate

This CL changes the TranslateInfoBarDelegate so that it does not remove
the infobar when ToggleTranslatableLanguageByPrefs and ToggleSiteBlacklist
are called for the following reasons:
1. These methods are doing more than their names suggest they do.
2. Their logic can be simplified if the call to remove the infobar is
   made in TranslateCompactInfoBar because these methods are only called
   in TranslateCompactInfoBar and the infobar always gets removed as a
   result of those calls.

Bug: 910994
Change-Id: Iad4919a69b41980d283cd33804107339f2ad6197
Reviewed-on: https://chromium-review.googlesource.com/c/1412733
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623373}
2 files changed