Take better control over Exceptions thrown in WebViewFactory.

Turn WebViewFactory.MissingWebViewPackageException into a non-runtime
exception to avoid potential bugs where we miss catching that exception.

Also introduce a new exception specifically for IOExceptions thrown in
getLoadFromApkPath().

Bug: 28736099
Test: make an Angler build.

Change-Id: Ib07257eaefaaa79d7ea45ba0f609be7263438f6c
1 file changed