Hide webview when showing a custom view

bug:6477718

Change-Id: Id3253096755ac4c174a791115f06dcb195b699c7
diff --git a/src/com/android/browser/BaseUi.java b/src/com/android/browser/BaseUi.java
index 42c7206..bb44336 100644
--- a/src/com/android/browser/BaseUi.java
+++ b/src/com/android/browser/BaseUi.java
@@ -527,12 +527,14 @@
         decor.addView(mFullscreenContainer, COVER_SCREEN_PARAMS);
         mCustomView = view;
         setFullscreen(true);
+        ((BrowserWebView) getWebView()).setVisibility(View.INVISIBLE);
         mCustomViewCallback = callback;
         mActivity.setRequestedOrientation(requestedOrientation);
     }
 
     @Override
     public void onHideCustomView() {
+        ((BrowserWebView) getWebView()).setVisibility(View.VISIBLE);
         if (mCustomView == null)
             return;
         setFullscreen(false);