Implementation for switching between recently used tabs using ctrl tilde or quoteleft.

chrome/browser/ui/tabs/tab_mru_list_manager.cc

+// Copyright (c) 2012 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.
+
+#include "chrome/browser/ui/tabs/tab_mru_list_manager.h"
+
+#include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
+
+///////////////////////////////////////////////////////////////////////////////
+// TabMRUListManager, public:
+
+///////////////////////////////////////////////////////////////////////////////
+// TabMRUListManager, TabStripModelObserver implementation:
+
+TabMRUListManager::TabMRUListManager(TabStripModel* tab_strip_model)
+    : tab_strip_model_(tab_strip_model) {
+  if (tab_strip_model_)

[sky, 2012/06/11 18:21:51]

When would the model ever be NULL?

[NaveenBobbili (Motorola), 2012/06/13 06:07:32]

Protection code. Unit tests would need this check.

+    tab_strip_model_->AddObserver(this);
+}
+
+TabMRUListManager::~TabMRUListManager() {
+  tabs_mru_list_.clear();
+  if (tab_strip_model_)
+    tab_strip_model_->RemoveObserver(this);
+}
+
+void TabMRUListManager::TabInsertedAt(TabContentsWrapper* contents,
+                                      int index,
+                                      bool foreground) {
+  if (foreground)
+    tabs_mru_list_.push_front(contents);
+  else
+    tabs_mru_list_.push_back(contents);
+}
+
+void TabMRUListManager::TabDetachedAt(TabContentsWrapper* contents,
+                                      int index) {
+  // Remove the index if found in MRU List
+  std::list<TabContentsWrapper*>::iterator it =
+      std::find(tabs_mru_list_.begin(), tabs_mru_list_.end(), contents);
+  if (it != tabs_mru_list_.end()) {
+    tabs_mru_list_.erase(it);
+  }
+}
+
+void TabMRUListManager::ActiveTabChanged(TabContentsWrapper* old_contents,
+                                         TabContentsWrapper* new_contents,
+                                         int index,
+                                         bool user_gesture) {
+  // Bring the activated tab content to the front of the list
+  std::list<TabContentsWrapper*>::iterator it =
+      std::find(tabs_mru_list_.begin(), tabs_mru_list_.end(), new_contents);
+  if (it != tabs_mru_list_.end()) {
+    tabs_mru_list_.push_front(*it);

[sky, 2012/06/11 18:21:51]

Why is the push conditional?

[NaveenBobbili (Motorola), 2012/06/13 06:07:32]

ActiveTabChanged should ideally be called after TabInsertTabAt. So I am double
checking if active tab is already in my list or not.

+    tabs_mru_list_.erase(it);
+  }
+}
+
+void TabMRUListManager::TabReplacedAt(TabStripModel* tab_strip_model,
+                                      TabContentsWrapper* old_contents,
+                                      TabContentsWrapper* new_contents,
+                                      int index) {
+  // Replace the tab contents accordingly in the list. If the tab contents are
+  // not found add to the end of the list.
+  std::list<TabContentsWrapper*>::iterator it =
+      std::find(tabs_mru_list_.begin(), tabs_mru_list_.end(), old_contents);
+  if (it != tabs_mru_list_.end()) {
+    tabs_mru_list_.insert(it,new_contents);

[sky, 2012/06/11 18:21:51]

space after ','

[NaveenBobbili (Motorola), 2012/06/13 06:07:32]

Done.

+    tabs_mru_list_.erase(it);
+  } else {
+    NOTREACHED();
+  }
+}
+
+void TabMRUListManager::TabStripEmpty() {
+  tabs_mru_list_.clear();
+}
+
+// Public Methods

[sky, 2012/06/11 18:21:51]

remove this comment.

[NaveenBobbili (Motorola), 2012/06/13 06:07:32]

Done.

+TabContentsWrapper* TabMRUListManager::GetNextMRUTab() {

[sky, 2012/06/11 18:21:51]

Order should match header.

[NaveenBobbili (Motorola), 2012/06/13 06:07:32]

Done.

+  // Only if there are more than one open tab we can switch.
+  if (tabs_mru_list_.size() < 2)
+    return NULL;
+
+  std::list<TabContentsWrapper*>::iterator it = tabs_mru_list_.begin();
+  std::advance(it, 1);
+  return *it;
+}