[Android] Fix the issue about file picker does not work.

This patch is to fix the issue about file picker does not work.
Upstream has added content URI to upload photos taken by camera,
so we follow it.

BUG=XWALK-2631
1. Yes.
2. It will not work without declaration. Generally, we can get URI from Uri.parse(String), I will investigate other solution to get URI from ```File```.
Thanks.