Move metadata key from Slice to SliceManager

Bug: 73741418 
Test: make -j20
Change-Id: Ia22b47d8b6d278944566641b07fcfb0fb7662d07
diff --git a/core/java/android/app/slice/SliceManager.java b/core/java/android/app/slice/SliceManager.java
index 3f13fff..a978e5b 100644
--- a/core/java/android/app/slice/SliceManager.java
+++ b/core/java/android/app/slice/SliceManager.java
@@ -60,6 +60,15 @@
     public static final String ACTION_REQUEST_SLICE_PERMISSION =
             "android.intent.action.REQUEST_SLICE_PERMISSION";
 
+    /**
+     * The meta-data key that allows an activity to easily be linked directly to a slice.
+     * <p>
+     * An activity can be statically linked to a slice uri by including a meta-data item
+     * for this key that contains a valid slice uri for the same application declaring
+     * the activity.
+     */
+    public static final String SLICE_METADATA_KEY = "android.metadata.SLICE_URI";
+
     private final ISliceManager mService;
     private final Context mContext;
     private final ArrayMap<Pair<Uri, SliceCallback>, ISliceListener> mListenerLookup =