[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
I see what you mean. FileProvider.getUriForFile() will get some infos from loading xml data, so ContentProvider should be declared in manifest. If there is other provider which can supply API to get URI for file, it also can be used. Thanks.