Clarify FLAG_BUBBLE semantics.

Bug: 129995314
Test: no code changes
Change-Id: I10b01a4e060217a793a39468e9d2788654ef3446
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index 15b571f..a869d85 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -618,11 +618,13 @@
     public static final int FLAG_CAN_COLORIZE = 0x00000800;
 
     /**
-     * Bit to be bitswised-ored into the {@link #flags} field that should be set if this
-     * notification is showing as a bubble. This will be set by the system if it is determined
-     * that your notification is allowed to be a bubble.
+     * Bit to be bitswised-ored into the {@link #flags} field that should be
+     * set by the system if this notification is showing as a bubble.
      *
-     * @see {@link Notification.Builder#setBubbleMetadata(BubbleMetadata)}
+     * Applications cannot set this flag directly; they should instead call
+     * {@link Notification.Builder#setBubbleMetadata(BubbleMetadata)} to
+     * request that a notification be displayed as a bubble, and then check
+     * this flag to see whether that request was honored by the system.
      */
     public static final int FLAG_BUBBLE = 0x00001000;
 
@@ -6253,7 +6255,7 @@
     }
 
     /**
-     * @return true if this is a notification that can show as a bubble.
+     * @return true if this notification is showing as a bubble
      *
      * @hide
      */