Add Downloads.Impl.COLUMN_MEDIASTORE_URI & DownloadColumns.Description.

Entries from DownloadProvider are added to MediaStore Downloads
collection. COLUMN_MEDIASTORE_URI will be used to track corresponding
entries in MediaProvider. We can't re-use COLUMN_MEDIAPROVIDER_URI
for this purpose because it is updateable by apps.

Bug: 120876251
Test: atest DownloadProviderTests
Test: atest cts/tests/app/src/android/app/cts/DownloadManagerTest.java
Test: atest MediaProviderTests
Test: atest cts/tests/tests/provider/src/android/provider/cts/MediaStore*
Change-Id: Ifd252c54f4ee739a31be2866896efac6696a088e

api/current.txt

@@ -38047,6 +38047,7 @@ package android.provider {
   }
 
   public static abstract interface MediaStore.DownloadColumns implements android.provider.MediaStore.MediaColumns {
+    field public static final java.lang.String DESCRIPTION = "description";
     field public static final java.lang.String DOWNLOAD_URI = "download_uri";
     field public static final java.lang.String REFERER_URI = "referer_uri";
   }

core/java/android/provider/Downloads.java

@@ -408,6 +408,15 @@ public final class Downloads {
          */
         public static final String COLUMN_MEDIAPROVIDER_URI = "mediaprovider_uri";
 
+        /**
+         * Similar to {@link #COLUMN_MEDIAPROVIDER_URI}, except this cannot be updated/queried
+         * by apps and will be the source of truth when updating/deleting download entries in
+         * MediaProvider database.
+         *
+         * <P>Type: TEXT</P>
+         */
+        public static final String COLUMN_MEDIASTORE_URI = "mediastore_uri";
+
         /**
          * The column that is used to remember whether the media scanner was invoked.
          * It can take the values: null or 0(not scanned), 1(scanned), 2 (not scannable).

core/java/android/provider/MediaStore.java

@@ -1025,6 +1025,11 @@ public final class MediaStore {
             return AUTHORITY_URI.buildUpon().appendPath(volumeName).appendPath("dir").build();
         }
 
+        /** @hide */
+        public static final Uri getContentUriForPath(String path) {
+            return getContentUri(getVolumeNameForPath(path));
+        }
+
         /**
          * Fields for master table for all media files.
          * Table also contains MediaColumns._ID, DATA, SIZE and DATE_MODIFIED.
@@ -1131,6 +1136,13 @@ public final class MediaStore {
          * Type: TEXT
          */
         String REFERER_URI = "referer_uri";
+
+        /**
+         * The description of the download.
+         * <p>
+         * Type: Text
+         */
+        String DESCRIPTION = "description";
     }
 
     /**

test-mock/src/android/test/mock/MockContentProvider.java

@@ -119,7 +119,7 @@ public class MockContentProvider extends ContentProvider {
 
         @Override
         public IBinder asBinder() {
-            throw new UnsupportedOperationException();
+            return MockContentProvider.this.getIContentProviderBinder();
         }
 
         @Override
@@ -278,6 +278,13 @@ public class MockContentProvider extends ContentProvider {
         return mIContentProvider;
     }
 
+    /**
+     * @hide
+     */
+    public IBinder getIContentProviderBinder() {
+        throw new UnsupportedOperationException("unimplemented mock method");
+    }
+
     /**
      * Like {@link #attachInfo(Context, android.content.pm.ProviderInfo)}, but for use
      * when directly instantiating the provider for testing.