Add system api for disabling touch events in wallpaper behind the window.

Bug: 18721756
Change-Id: I40b749a9916536d52042e5dd49a23575bedad754

core/java/android/view/Window.java

@@ -18,6 +18,7 @@ package android.view;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SystemApi;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.content.res.Resources;
@@ -900,6 +901,14 @@ public abstract class Window {
         }
     }
 
+    /** @hide */
+    @SystemApi
+    public void setDisableWallpaperTouchEvents(boolean disable) {
+        setPrivateFlags(disable
+                ? WindowManager.LayoutParams.PRIVATE_FLAG_DISABLE_WALLPAPER_TOUCH_EVENTS : 0,
+                WindowManager.LayoutParams.PRIVATE_FLAG_DISABLE_WALLPAPER_TOUCH_EVENTS);
+    }
+
     /** @hide */
     public abstract void alwaysReadCloseOnTouchAttr();