Remove the public APIs for allow rich content.

1. Mark @hide for "Drawable loadAnimatedImage(Context)" and "String loadHtmlDescription(PackageManager)".
2. Move common function into util.

Bug: 149516547
Bug: 142532186
Test: maunal test
Change-Id: I4f734a496938f64bcde990268e11a2d1a5be4771
Merged-In: I4f734a496938f64bcde990268e11a2d1a5be4771
(cherry picked from commit a2f7f849383cc91aca6e3b74ffdabc1343c2ca55)
4 files changed