Disable translate when there is no API key

There is a new ChromePublic.apk target which is to Android Chrome as
desktop Chromium is to desktop Chrome. ChromePublic lacks an API key,
so many Google APIs are not available. I recently surveyed all the
Chrome features which seem to depend an Google APIs. Some still
worked. Most failed gracefully. Translate was the only one that failed
ungracefully; in ChromePublic, the dialog pops up offering to
translate a foreign page, but if you accept, nothing happens. We
should disable translate (not show the dialog) in this case to avoid
this bad UX.


Review URL: https://codereview.chromium.org/1185703007

Cr-Commit-Position: refs/heads/master@{#339292}
7 files changed