Ensure default folders and Camera folders are always visible

".nomedia" presence in a directory makes MediaProvider treat that
directory as a hidden directory. MEDIA_TYPE for all files in the hidden
directory will be set to MEDIA_TYPE_NONE hence apps can't use content
uris of media(like images or video) for files in the hidden directory.

Top level default directories and Camera directories are well-known
directories and should always be visible despite ".nomedia" presense.
Any unintentional/intentional ".nomedia" file addition to these
directories shouldn't hurt other apps that are dependent on these
directories to be always visible.

Changed isDirectoryHidden to ignore any ".nomedia" presence in top level
default directories and "DCIM/Camera", and treat these directories as
non-hidden.

Bug: 168830497
Test: atest
android.scopedstorage.cts.host.ScopedStorageHostTest#testCanWriteToDCIMCameraWithNomedia
Test: atest
com.android.providers.media.scan.ModernMediaScannerTest#testVisibleDefaultFolders
Merged-In: I6a529a1d123134de238f4c494d04037137ee252c
Change-Id: I6a529a1d123134de238f4c494d04037137ee252c
3 files changed