Actually remove the subwindow.

Bug 2748202

Change-Id: I133e12167cb8b68d0fc7e0f0d3c9bfe727334e81
diff --git a/src/com/android/browser/Tab.java b/src/com/android/browser/Tab.java
index 5350a18..07310bf 100644
--- a/src/com/android/browser/Tab.java
+++ b/src/com/android/browser/Tab.java
@@ -1433,7 +1433,7 @@
                     if (mSubView.copyBackForwardList().getSize() == 0) {
                         // This subwindow was opened for the sole purpose of
                         // downloading a file. Remove it.
-                        dismissSubWindow();
+                        mActivity.dismissSubWindow(Tab.this);
                     }
                 }
             });