Improve tab switcher open perf

 Bug: 5379115

Change-Id: I5e5bfcfead4c54deb49af94de6f6526bd2710567
diff --git a/src/com/android/browser/BaseUi.java b/src/com/android/browser/BaseUi.java
index ed21b20..26f90b6 100644
--- a/src/com/android/browser/BaseUi.java
+++ b/src/com/android/browser/BaseUi.java
@@ -801,16 +801,19 @@
         mHandler.sendMessageDelayed(msg, duration);
     }
 
-    private Handler mHandler = new Handler() {
+    protected Handler mHandler = new Handler() {
 
         @Override
         public void handleMessage(Message msg) {
             if (msg.what == MSG_HIDE_TITLEBAR) {
                 suggestHideTitleBar();
             }
+            BaseUi.this.handleMessage(msg);
         }
     };
 
+    protected void handleMessage(Message msg) {}
+
     @Override
     public void showWeb(boolean animate) {
         mUiController.hideCustomView();