Enable media provider to perform its own hidden API processing

Previously, the hidden API encoding of the media provider boot dex
jars, i.e. those dex jars that media provider contributes to the
bootclasspath were done as part of the monolithic hidden API
processing. This change causes the encoding to be done by the media
provider's bootclasspath_fragment.

This change involves the following:
* Addition of the fragments property to the media provider's
  bootclasspath_fragment module to list all the other
  bootclasspath_fragment modules on which this depends.
* Addition of the additional_stubs property to add stubs for APIs that
  are not provided by another bootclasspath_fragment.
* Moving hidden API flag file entries related to media provider from
  the flag files in frameworks/base/boot/hiddenapi directory into the
  media provider directory with an appropriate OWNERS file to allow
  them to be managed by the Soong and compat team.
* Addition of a PREUPLOAD.cfg hook script to ensure that the flag files
  are sorted.

The build automatically checks that the hidden API flags which are
computed by media provider and encoded into its boot dex jars match
those that are generated by the monolithic processing so this is
guaranteed to be safe.

Bug: 179354495
Test: m com.android.mediaprovider
      - ensure that the generated APEX is byte-for-byte identical
        before and after these changes.
      m out/soong/hiddenapi/hiddenapi-flags.csv
      - make sure that they are not changed by this.
Change-Id: I32e2d726f831a25dd12605a82dde01bd885bb460
diff --git a/apex/hiddenapi/hiddenapi-max-target-o-low-priority.txt b/apex/hiddenapi/hiddenapi-max-target-o-low-priority.txt
new file mode 100644
index 0000000..7c59c96
--- /dev/null
+++ b/apex/hiddenapi/hiddenapi-max-target-o-low-priority.txt
@@ -0,0 +1,27 @@
+Landroid/provider/MediaStore$Audio$AudioColumns;->ALBUM_ARTIST:Ljava/lang/String;
+Landroid/provider/MediaStore$Audio$AudioColumns;->COMPILATION:Ljava/lang/String;
+Landroid/provider/MediaStore$Audio$AudioColumns;->GENRE:Ljava/lang/String;
+Landroid/provider/MediaStore$Audio$AudioColumns;->TITLE_RESOURCE_URI:Ljava/lang/String;
+Landroid/provider/MediaStore$Audio$Media;->EXTERNAL_PATHS:[Ljava/lang/String;
+Landroid/provider/MediaStore$Audio$Radio;-><init>()V
+Landroid/provider/MediaStore$Files;->getDirectoryUri(Ljava/lang/String;)Landroid/net/Uri;
+Landroid/provider/MediaStore$Images$Media;->StoreThumbnail(Landroid/content/ContentResolver;Landroid/graphics/Bitmap;JFFI)Landroid/graphics/Bitmap;
+Landroid/provider/MediaStore$InternalThumbnails;-><init>()V
+Landroid/provider/MediaStore$InternalThumbnails;->cancelThumbnailRequest(Landroid/content/ContentResolver;JLandroid/net/Uri;J)V
+Landroid/provider/MediaStore$InternalThumbnails;->DEFAULT_GROUP_ID:I
+Landroid/provider/MediaStore$InternalThumbnails;->FULL_SCREEN_KIND:I
+Landroid/provider/MediaStore$InternalThumbnails;->getMiniThumbFromFile(Landroid/database/Cursor;Landroid/net/Uri;Landroid/content/ContentResolver;Landroid/graphics/BitmapFactory$Options;)Landroid/graphics/Bitmap;
+Landroid/provider/MediaStore$InternalThumbnails;->getThumbnail(Landroid/content/ContentResolver;JJILandroid/graphics/BitmapFactory$Options;Landroid/net/Uri;Z)Landroid/graphics/Bitmap;
+Landroid/provider/MediaStore$InternalThumbnails;->MICRO_KIND:I
+Landroid/provider/MediaStore$InternalThumbnails;->MINI_KIND:I
+Landroid/provider/MediaStore$InternalThumbnails;->PROJECTION:[Ljava/lang/String;
+Landroid/provider/MediaStore$InternalThumbnails;->sThumbBuf:[B
+Landroid/provider/MediaStore$InternalThumbnails;->sThumbBufLock:Ljava/lang/Object;
+Landroid/provider/MediaStore$MediaColumns;->MEDIA_SCANNER_NEW_OBJECT_ID:Ljava/lang/String;
+Landroid/provider/MediaStore;->CONTENT_AUTHORITY_SLASH:Ljava/lang/String;
+Landroid/provider/MediaStore;->getDocumentUri(Landroid/content/ContentResolver;Ljava/lang/String;Ljava/util/List;)Landroid/net/Uri;
+Landroid/provider/MediaStore;->getFilePath(Landroid/content/ContentResolver;Landroid/net/Uri;)Ljava/lang/String;
+Landroid/provider/MediaStore;->PARAM_DELETE_DATA:Ljava/lang/String;
+Landroid/provider/MediaStore;->RETRANSLATE_CALL:Ljava/lang/String;
+Landroid/provider/MediaStore;->TAG:Ljava/lang/String;
+Landroid/provider/MediaStore;->UNHIDE_CALL:Ljava/lang/String;