Backed out changeset 6f5998401e95 (bug 1517846) for Android api-lint failure on a CLOSED TREE

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoView.java

@@ -242,14 +242,6 @@ public class GeckoView extends FrameLayout {
         }
     }
 
-    /**
-     * Unsets the current session from this instance and returns it, if any. You must call
-     * this before {@link #setSession(GeckoSession)} if there is already an open session
-     * set for this instance.
-     *
-     * @return The {@link GeckoSession} that was set for this instance. May be null.
-     */
-    @UiThread
     public @Nullable GeckoSession releaseSession() {
         ThreadUtils.assertOnUiThread();
 
@@ -287,12 +279,9 @@ public class GeckoView extends FrameLayout {
 
     /**
      * Attach a session to this view. The session should be opened before
-     * attaching. If this instance already has an open session, you must use
-     * {@link #releaseSession()} first, otherwise {@link IllegalStateException}
-     * will be thrown. This is to avoid potentially leaking the currently opened session.
+     * attaching.
      *
      * @param session The session to be attached.
-     * @throws IllegalArgumentException if an existing open session is already set.
      */
     public void setSession(@NonNull final GeckoSession session) {
         ThreadUtils.assertOnUiThread();
@@ -307,13 +296,9 @@ public class GeckoView extends FrameLayout {
     /**
      * Attach a session to this view. The session should be opened before
      * attaching or a runtime needs to be provided for automatic opening.
-     * If this instance already has an open session, you must use
-     * {@link #releaseSession()} first, otherwise {@link IllegalStateException}
-     * will be thrown. This is to avoid potentially leaking the currently opened session.
      *
      * @param session The session to be attached.
      * @param runtime The runtime to be used for opening the session.
-     * @throws IllegalArgumentException if an existing open session is already set.
      */
     public void setSession(@NonNull final GeckoSession session,
                            @Nullable final GeckoRuntime runtime) {