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

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

Index: chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
diff --git a/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java b/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
index 183d6770c60ef07a707ba575135a1be1088fa3da..99b04521ee33026215b16c4de24ac2c2e3615e2f 100644
--- a/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
+++ b/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
@@ -6,8 +6,10 @@ 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;
 
@@ -16,6 +18,7 @@ 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;
@@ -40,13 +43,14 @@ public class TabManager extends LinearLayout {
     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
@@ -80,6 +84,7 @@ public class TabManager extends LinearLayout {
 
         mToolbar = (ChromeShellToolbar) findViewById(R.id.toolbar);
         mToolbar.setTabManager(this);
+        mTabModelWrapper = mTabModelSelector.getTabModelWrapper();
         mContentViewRenderView = new ContentViewRenderView(getContext()) {
             @Override
             protected void onReadyToRender() {
@@ -183,19 +188,47 @@ public class TabManager extends LinearLayout {
         contentViewCore.onShow();
     }
 
-    /**
-     * Toggles the tab switcher visibility.
+    /*
+     * Hide the tab switcher.
      */
-    public void toggleTabSwitcher() {
-        mTabModelSelector.toggleTabSwitcher();
+    public void hideTabSwitcher() {
+        if (mTabModelWrapper == null) return;
+        mToolbar.showAddButton(false);

[Bernhard Bauer, 2014/11/10 13:58:33]

Is there some method to where these calls appear? I could see doing both at the
beginning of the method, both at the end, or even one at the beginning and one
at the end (making the methods inverse to each other), but this seems a bit...
random.

[divya.bansal, 2014/11/11 05:18:19]

Done.

+        ViewParent parent = mTabModelWrapper.getParent();
+        if (parent != null) {
+            assert parent == mContentViewHolder;
+            mContentViewHolder.removeView(mTabModelWrapper);
+        }
+    }
+
+    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() {
-        return mTabModelSelector.isTabSwitcherVisible();
+        return mTabModelWrapper != null && mTabModelWrapper.getParent() == mContentViewHolder;
     }
 
-    public void hideTabSwitcher() {
-        mTabModelSelector.hideTabSwitcher();
+    /**
+     * Toggles the tab switcher visibility.
+     */
+    public void toggleTabSwitcher() {
+        if (!isTabSwitcherVisible()) {
+            showTabSwitcher();
+        } else {
+            hideTabSwitcher();
+        }
     }
 
     /**