Update Javadoc comments for ConnectivityDiagnostics constants.

API Council feedback requested adding documentation for detection method
constants used in DataStallReport to indicate how the Data Stall was
detected.

Bug: 150598997
Test: n/a
Change-Id: Ib08f05562dd4b17973eeee97452d9f56d37e80fe
Merged-In: Ib08f05562dd4b17973eeee97452d9f56d37e80fe
(cherry picked from commit 52d9e61121883945931de533b5cfd44da30c0248)
diff --git a/core/java/android/net/ConnectivityDiagnosticsManager.java b/core/java/android/net/ConnectivityDiagnosticsManager.java
index d009144..1710ccb 100644
--- a/core/java/android/net/ConnectivityDiagnosticsManager.java
+++ b/core/java/android/net/ConnectivityDiagnosticsManager.java
@@ -368,7 +368,14 @@
 
     /** Class that includes information for a suspected data stall on a specific Network */
     public static final class DataStallReport implements Parcelable {
+        /**
+         * Indicates that the Data Stall was detected using DNS events.
+         */
         public static final int DETECTION_METHOD_DNS_EVENTS = 1;
+
+        /**
+         * Indicates that the Data Stall was detected using TCP metrics.
+         */
         public static final int DETECTION_METHOD_TCP_METRICS = 2;
 
         /** @hide */