Do not attempt to download favicons with 404 status in WebView

This issue was fixed for Chromium (crbug.com/39402). This patch gets the
relevant parts of the fixing patch for Android WebView.

BUG=39402

Review URL: https://codereview.chromium.org/255503004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267192 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed