Fixing crash in some full screen cases

If an event makes it into the NonClientDecor and the
application is maximized, it should not process it.

Bug: 23489031
Change-Id: I661ea207522bbea64f297cd63cc2b5da192d47ae
diff --git a/core/java/com/android/internal/widget/NonClientDecorView.java b/core/java/com/android/internal/widget/NonClientDecorView.java
index 92812f8..372d934 100644
--- a/core/java/com/android/internal/widget/NonClientDecorView.java
+++ b/core/java/com/android/internal/widget/NonClientDecorView.java
@@ -124,6 +124,10 @@
         // input device we are listening to.
         switch (e.getActionMasked()) {
             case MotionEvent.ACTION_DOWN:
+                if (!mShowDecor) {
+                    // When there is no decor we should not react to anything.
+                    return false;
+                }
                 // A drag action is started if we aren't dragging already and the starting event is
                 // either a left mouse button or any other input device.
                 if (!mDragging &&