Fix issue #2133206: dialogs/menus should auto-dismiss when screen turns off

Lot of infrastructure for more things to go away when "clear system dialogs"
happens, and now do this when we turn on the lock screen.

Change-Id: I567130296fe47ce82df065ed58ef21b37416ceaf

core/java/com/android/internal/view/BaseIWindow.java

@@ -90,6 +90,9 @@ public class BaseIWindow extends IWindow.Stub {
     public void executeCommand(String command, String parameters, ParcelFileDescriptor out) {
     }
     
+    public void closeSystemDialogs(String reason) {
+    }
+    
     public void dispatchWallpaperOffsets(float x, float y, boolean sync) {
         if (sync) {
             try {