Adding option for adding new tab in tab manager for chrome shell.

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;
 import android.view.ViewGroup;
+import android.view.ViewParent;
 import android.widget.FrameLayout;
 import android.widget.LinearLayout;
 
 import org.chromium.chrome.browser.EmptyTabObserver;
 import org.chromium.chrome.browser.Tab;
 import org.chromium.chrome.browser.tabmodel.EmptyTabModelObserver;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabLaunchType;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
+import org.chromium.chrome.browser.widget.accessibility.AccessibilityTabModelWrapper;
 import org.chromium.content.browser.ContentVideoViewClient;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content.browser.ContentViewRenderView;
 import org.chromium.content_public.browser.LoadUrlParams;
 import org.chromium.ui.base.PageTransition;
 import org.chromium.ui.base.WindowAndroid;
 
 /**
  * The TabManager hooks together all of the related {@link View}s that are used to represent
  * a {@link ChromeShellTab}.  It properly builds a {@link ChromeShellTab} and makes sure that the
  * {@link ChromeShellToolbar} and {@link ContentViewRenderView} show the proper content.
  */
 public class TabManager extends LinearLayout {
     private static final String DEFAULT_URL = "http://www.google.com";
 
     private ViewGroup mContentViewHolder;
     private ContentViewRenderView mContentViewRenderView;
     private ChromeShellToolbar mToolbar;
 
     private ChromeShellTab mCurrentTab;
 
     private String mStartupUrl = DEFAULT_URL;
 
     private ChromeShellTabModelSelector mTabModelSelector;
+    private AccessibilityTabModelWrapper mTabModelWrapper;
 
     private final EmptyTabModelObserver mTabModelObserver = new EmptyTabModelObserver() {
         @Override
         public void didSelectTab(Tab tab, TabSelectionType type, int lastId) {
             assert tab instanceof ChromeShellTab;
             setCurrentTab((ChromeShellTab) tab);
-            mTabModelSelector.hideTabSwitcher();
+            hideTabSwitcher();
         }
 
         @Override
         public void willCloseTab(Tab tab, boolean animate) {
             if (tab == mCurrentTab) setCurrentTab(null);
         }
     };
 
     /**
      * @param context The Context the view is running in.
@@ skipping 116 matching lines @@
 
     private void setupContent() {
         View view = mCurrentTab.getView();
         ContentViewCore contentViewCore = mCurrentTab.getContentViewCore();
         mContentViewHolder.addView(view);
         mContentViewRenderView.setCurrentContentViewCore(contentViewCore);
         view.requestFocus();
         contentViewCore.onShow();
     }
 
+    /*

[Bernhard Bauer, 2014/11/11 09:08:22]

Add a second asterisk here to make this a Javadoc comment.

[divya.bansal, 2014/11/11 09:29:51]

Done.

+     * Hide the tab switcher.
+     */
+    public void hideTabSwitcher() {
+        if (mTabModelWrapper == null) return;
+        ViewParent parent = mTabModelWrapper.getParent();
+        if (parent != null) {
+            assert parent == mContentViewHolder;
+            mContentViewHolder.removeView(mTabModelWrapper);
+        }
+        mToolbar.showAddButton(false);
+    }
+
+    private void showTabSwitcher() {
+        if (mTabModelWrapper == null) {
+            mTabModelWrapper = (AccessibilityTabModelWrapper) LayoutInflater.from(
+                    mContentViewHolder.getContext()).inflate(
+                            R.layout.accessibility_tab_switcher, null);
+            mTabModelWrapper.setup(null);
+            mTabModelWrapper.setTabModelSelector(mTabModelSelector);
+        }
+
+        if (mTabModelWrapper.getParent() == null) {
+            mContentViewHolder.addView(mTabModelWrapper);
+        }
+        mToolbar.showAddButton(true);
+    }
+
+    public boolean isTabSwitcherVisible() {

[Bernhard Bauer, 2014/11/11 09:08:22]

Please add a Javadoc comment.

[divya.bansal, 2014/11/11 09:29:51]

Done.

+        return mTabModelWrapper != null && mTabModelWrapper.getParent() == mContentViewHolder;
+    }
+
     /**
      * Toggles the tab switcher visibility.
      */
     public void toggleTabSwitcher() {
-        mTabModelSelector.toggleTabSwitcher();
-    }
-
-    public boolean isTabSwitcherVisible() {
-        return mTabModelSelector.isTabSwitcherVisible();
-    }
-
-    public void hideTabSwitcher() {
-        mTabModelSelector.hideTabSwitcher();
+        if (!isTabSwitcherVisible()) {
+            showTabSwitcher();
+        } else {
+            hideTabSwitcher();
+        }
     }
 
     /**
      * Opens a URL in the current tab if one exists, or in a new tab otherwise.
      * @param url The URL to open.
      * @return The tab used to open the provided URL.
      */
     public Tab openUrl(String url) {
         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);
     }
 }