Propagate setImeWindowStatus() to WMS

setImeWindowStatus() introduced in the previous CL [1] can help
WindowManagerService (WMS) address Bug 34628091.  As a preparation
this CL has InputMethodManagerService propagate relevant information
to WMS WMS for later use.

 [1]: I9921b381e02106dbffff5e0b3d13f0a1245ce807
      db2afde0e584904ee4ce115ce176a4dfe1773990

Test: Verified the callback in WindowManagerService as follows:
       1. Rebuild the system with DEBUG_INPUT_METHOD=true
       2. adb logcat -s WindowManager:*
            to make sure the visibility passed to
            WindowManagerService#updateInputMethodWindowStatus matches
            to the actual IME window visibility
Bug: 34628091
Bug: 35079353
Change-Id: I54fb1faf513883a54293a756e4c9d2ae9453d778

core/java/android/view/WindowManagerInternal.java

@@ -281,6 +281,25 @@ public abstract class WindowManagerInternal {
      */
     public abstract void clearLastInputMethodWindowForTransition();
 
+    /**
+     * Notifies WindowManagerService that the current IME window status is being changed.
+     *
+     * <p>Only {@link com.android.server.InputMethodManagerService} is the expected and tested
+     * caller of this method.</p>
+     *
+     * @param imeToken token to track the active input method. Corresponding IME windows can be
+     *                 identified by checking {@link android.view.WindowManager.LayoutParams#token}.
+     *                 Note that there is no guarantee that the corresponding window is already
+     *                 created
+     * @param imeWindowVisible whether the active IME thinks that its window should be visible or
+     *                         hidden, no matter how WindowManagerService will react / has reacted
+     *                         to corresponding API calls.  Note that this state is not guaranteed
+     *                         to be synchronized with state in WindowManagerService.
+     * @param targetWindowToken token to identify the target window that the IME is associated with.
+     */
+    public abstract void updateInputMethodWindowStatus(IBinder imeToken, boolean imeWindowVisible,
+            IBinder targetWindowToken);
+
     /**
       * Returns true when the hardware keyboard is available.
       */