composer: add seamlessPossible callback to composer 2.4

Add a callback to notify the client it should retry a
setActiveConfigWithConstraints call in case of SEAMLESS_NOT_POSSIBLE error.

Test: rev up composer to 2.4
Bug: 141329414
Change-Id: I6176638fde937e3916f58cc577d50cb755997c61
diff --git a/graphics/composer/2.4/IComposerCallback.hal b/graphics/composer/2.4/IComposerCallback.hal
index fea24a1..f343cee 100644
--- a/graphics/composer/2.4/IComposerCallback.hal
+++ b/graphics/composer/2.4/IComposerCallback.hal
@@ -42,4 +42,14 @@
      * @param updatedTimeline is the new timeline for the vsync period change.
      */
     oneway onVsyncPeriodTimingChanged(Display display, VsyncPeriodChangeTimeline updatedTimeline);
+
+    /**
+     * Notifies the client that the conditions which previously led to returning
+     * SEAMLESS_NOT_POSSIBLE from setActiveConfigWithConstraints have changed and now seamless may
+     * be possible. Client should retry calling setActiveConfigWithConstraints.
+     *
+     * @param display is a display setActiveConfigWithConstraints previously failed with
+     * SEAMLESS_NOT_POSSIBLE.
+     */
+    oneway onSeamlessPossible(Display display);
 };