Set sub window to scrollbars_outside_overlay to
match the style we use for the main window.

Fix http://b/issue?id=2531179
diff --git a/src/com/android/browser/Tab.java b/src/com/android/browser/Tab.java
index 84bb018..8cbaa4d 100644
--- a/src/com/android/browser/Tab.java
+++ b/src/com/android/browser/Tab.java
@@ -1417,6 +1417,7 @@
             mSubViewContainer = mInflateService.inflate(
                     R.layout.browser_subwindow, null);
             mSubView = (WebView) mSubViewContainer.findViewById(R.id.webview);
+            mSubView.setScrollBarStyle(View.SCROLLBARS_OUTSIDE_OVERLAY);
             // use trackball directly
             mSubView.setMapTrackballToArrowKeys(false);
             mSubView.setWebViewClient(new SubWindowClient(mWebViewClient));