Add window focus / visibility changed signals to AllAppsSearchPlugin

Change-Id: Ieb48e398cca85dd4343e37fef0015f5e4fece86f

src_plugins/com/android/systemui/plugins/AllAppsSearchPlugin.java

@@ -42,6 +42,12 @@ public interface AllAppsSearchPlugin extends Plugin {
     void onStateTransitionStart(int fromState, int toState);
     void onStateTransitionComplete(int state);
 
+    /**
+     * Send launcher window focus and visibility changed signals.
+     */
+    void onWindowFocusChanged(boolean hasFocus);
+    void onWindowVisibilityChanged(int visibility);
+
     /**
      * Send signal when user starts typing, perform search, when search ends
      */