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

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelBase.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.browser.tabmodel;
 
 import org.chromium.base.ObserverList;
 import org.chromium.base.TraceEvent;
 import org.chromium.chrome.browser.Tab;
 import org.chromium.chrome.browser.util.MathUtils;
@@ skipping 435 matching lines @@
         // TODO(dtrainor): Update the list of undoable tabs instead of committing it.
         if (!canUndo) commitAllTabClosures();
 
         // Cancel any media currently playing.
         if (canUndo) {
             WebContents webContents = tab.getWebContents();
             if (webContents != null) webContents.releaseMediaPlayers();
         }
 
         mTabs.remove(tab);
+        for (TabModelObserver obs : mObservers) obs.didCloseTab(tab);

[Bernhard Bauer, 2014/11/19 09:57:34]

Why this change? didCloseTab() means that closing the tab is done, but here we
are just starting to close the tab (it's not instantaneous because there's
animations etc.)

[divya.bansal, 2014/11/19 10:04:24]

Here after tab is removed didclosetab is called.If didclosetab() in
finalizetabclosure is used, that is not instantaneous and there after tab is
removed focus goes to url bar and then after some time new tab opens.
But here its happening instantaneously.

[Bernhard Bauer, 2014/11/19 10:06:45]

Right, but you can't just go ahead and change the semantics of existing
notifications. That is almost guaranteed to break things.

Does using willCloseTab not work?

[divya.bansal, 2014/11/19 10:09:39]

willCloseTab() is set even before tab is removed in starttabclosure(), so there
still count !=0 and if in that i open a new tab, after that tab is removed.

[Bernhard Bauer, 2014/11/19 10:13:53]

Would it work if you call createNewTab() if the count is 1?

[divya.bansal, 2014/11/19 12:07:57]

Done.

 
         boolean nextIsIncognito = nextTab == null ? false : nextTab.isIncognito();
         int nextTabId = nextTab == null ? Tab.INVALID_TAB_ID : nextTab.getId();
         int nextTabIndex = nextTab == null ? INVALID_TAB_INDEX : TabModelUtils.getTabIndexById(
                 mModelDelegate.getModel(nextIsIncognito), nextTabId);
 
         if (nextTab != currentTab) {
             if (nextIsIncognito != isIncognito()) mIndex = indexOf(adjacentTab);
 
             TabModel nextModel = mModelDelegate.getModel(nextIsIncognito);
             nextModel.setIndex(nextTabIndex,
                     uponExit ? TabSelectionType.FROM_EXIT : TabSelectionType.FROM_CLOSE);
         } else {
             mIndex = nextTabIndex;
         }
 
         if (!canUndo) mRewoundList.resetRewoundState();
     }
 
     /**
      * Actually closes and cleans up {@code tab}.
      * @param tab The {@link Tab} to close.
      */
     private void finalizeTabClosure(Tab tab) {
-        for (TabModelObserver obs : mObservers) obs.didCloseTab(tab);
         tab.destroy();
     }
 
     private class RewoundList implements TabList {
         /**
          * A list of {@link Tab}s that represents the completely rewound list (if all
          * rewindable closes were undone). If there are no possible rewindable closes this list
          * should match {@link #mTabs}.
          */
         private final List<Tab> mRewoundTabs = new ArrayList<Tab>();
@@ skipping 124 matching lines @@
     @Override
     public int index() {
         return mIndex;
     }
 
     @Override
     protected boolean isSessionRestoreInProgress() {
         return mModelDelegate.isSessionRestoreInProgress();
     }
 }