WebView: Support loading .svgz assets/resources

Loading .svgz files from the web works because of a special case in
URLRequestFileJob::SetUpSourceStream(). Add a special case in
AndroidProtocolHandler so that e.g.
WebView.loadUrl("file:///android_asset/foo.svgz") works as well.

BUG=854282

Change-Id: I995f8b602bd6e3b05818ede763f3774465850d82
Reviewed-on: https://chromium-review.googlesource.com/1134429
Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Paul Miller <paulmiller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574634}
5 files changed