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

chrome/browser/ui/tabs/mru_tab_controller.cc

Index: chrome/browser/ui/tabs/mru_tab_controller.cc
diff --git a/chrome/browser/ui/tabs/mru_tab_controller.cc b/chrome/browser/ui/tabs/mru_tab_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5c172c077ab4b56941b3f75027d9022efacab90a
--- /dev/null
+++ b/chrome/browser/ui/tabs/mru_tab_controller.cc
@@ -0,0 +1,103 @@
+// 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/mru_tab_controller.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+
+#include "chrome/browser/ui/tab_contents/tab_contents.h"
+
+///////////////////////////////////////////////////////////////////////////////
+// MRUTabController, public:
+
+///////////////////////////////////////////////////////////////////////////////
+// MRUTabController, TabStripModelObserver implementation:
+
+MRUTabController::MRUTabController(TabStripModel* tab_strip_model)
+    : tab_strip_model_(tab_strip_model),
+      can_update_stack_(true) {
+  tab_strip_model_->AddObserver(this);
+}
+
+MRUTabController::~MRUTabController() {
+  tabs_mru_list_.clear();
+  if (tab_strip_model_)
+    tab_strip_model_->RemoveObserver(this);
+}
+
+void MRUTabController::TabInsertedAt(TabContents* contents,
+                                      int index,
+                                      bool foreground) {
+  if (foreground)
+    tabs_mru_list_.push_front(contents);
+  else
+    tabs_mru_list_.push_back(contents);
+}
+
+void MRUTabController::TabDetachedAt(TabContents* contents,
+                                      int index) {
+  // Remove the index if found in MRU List
+  std::list<TabContents*>::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 MRUTabController::ActiveTabChanged(TabContents* old_contents,
+                                         TabContents* new_contents,
+                                         int index,
+                                         bool user_gesture) {
+  if (!can_update_stack_)
+    return;
+
+  // Bring the activated tab content to the front of the list
+  std::list<TabContents*>::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);
+    tabs_mru_list_.erase(it);
+  }
+}
+
+void MRUTabController::TabReplacedAt(TabStripModel* tab_strip_model,
+                                      TabContents* old_contents,
+                                      TabContents* 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<TabContents*>::iterator it =
+      std::find(tabs_mru_list_.begin(), tabs_mru_list_.end(), old_contents);
+  if (it != tabs_mru_list_.end() && *it != tabs_mru_list_.front()) {
+    tabs_mru_list_.insert(it, new_contents);
+    tabs_mru_list_.erase(it);
+  } else {
+    NOTREACHED();
+  }
+}
+
+void MRUTabController::TabStripEmpty() {
+  tabs_mru_list_.clear();
+}
+
+TabContents* MRUTabController::GetPreviousMRUTab() {
+  // Only if there are more than one open tab we can switch.
+  if (tabs_mru_list_.size() < 2)
+    return NULL;
+
+  std::list<TabContents*>::iterator it = tabs_mru_list_.begin();
+  return *(++it);
+}
+
+void MRUTabController::PauseStackUpdates() {
+  can_update_stack_ = false;
+}
+
+void MRUTabController::CommitActiveTabChanges() {
+  if (can_update_stack_)
+    return;
+
+  can_update_stack_ = true;
+  TabContents* active_tab = tab_strip_model_->GetActiveTabContents();
+  ActiveTabChanged(active_tab, active_tab, 0, true);
+}