Opening new "about:blank" tab if all tabs are closed in tab switcher mode.

chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.shell;
 
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
@@ skipping 40 matching lines @@
         public void didSelectTab(Tab tab, TabSelectionType type, int lastId) {
             assert tab instanceof ChromeShellTab;
             setCurrentTab((ChromeShellTab) tab);
             hideTabSwitcher();
         }
 
         @Override
         public void willCloseTab(Tab tab, boolean animate) {
             if (tab == mCurrentTab) setCurrentTab(null);
         }
+
+        @Override
+        public void didCloseTab(Tab tab) {
+            ensureTabExists();
+        }
+
     };
 
     /**
      * @param context The Context the view is running in.
      * @param attrs   The attributes of the XML tag that is inflating the view.
      */
     public TabManager(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
@@ skipping 178 matching lines @@
         LoadUrlParams loadUrlParams = new LoadUrlParams(url);
         loadUrlParams.setTransitionType(PageTransition.TYPED | PageTransition.FROM_ADDRESS_BAR);
         Tab tab = mTabModelSelector.getCurrentTab();
         if (tab != null) {
             tab.loadUrl(loadUrlParams);
             return tab;
         }
         return createTab(url, TabLaunchType.FROM_KEYBOARD);
     }
 }