Structure MediaProvider as an APEX.

Based on guidance from the Mainline team, we're placing the
MediaProvider APK inside a new APEX, as this will allow us to
move MediaStore.java inside the module boundary in a future CL.

As part of this restructuring, we need the pre-Mainline APK to
remain intact to preserve the user's media database.  There is
already logic in place from previous CLs that will migrate data
from the pre-Mainline to the post-Mainline world, including tests
to verify that the migration works.

Bug: 144247087
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: I571eccbb2950a7c518a682eae3350ba7ef9bd804

CleanSpec.mk

@@ -713,6 +713,9 @@ $(call add-clean-step, rm -rf $(PRODUCT_OUT)/vendor/etc/vintf/manifest/android.h
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/apex/com.android.cellbroadcast.apex)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/apex/com.android.cellbroadcast)
 
+# Remove MediaProvider after moving into APEX
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/priv-app/MediaProvider)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************

target/product/base_system.mk

@@ -58,6 +58,7 @@ PRODUCT_PACKAGES += \
     com.android.location.provider \
     com.android.media \
     com.android.media.swcodec \
+    com.android.mediaprovider \
     com.android.permission \
     com.android.resolv \
     com.android.neuralnetworks \
@@ -204,7 +205,7 @@ PRODUCT_PACKAGES += \
     mediaextractor \
     mediametrics \
     media_profiles_V1_0.dtd \
-    MediaProvider \
+    MediaProviderLegacy \
     mediaserver \
     mke2fs \
     monkey \