Split Screen mode implementation

athena/wm/mru_window_tracker.cc

Index: athena/wm/mru_window_tracker.cc
diff --git a/athena/wm/mru_window_tracker.cc b/athena/wm/mru_window_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b898945d61ff7efb7f3311f1df8273e5404847ab
--- /dev/null
+++ b/athena/wm/mru_window_tracker.cc
@@ -0,0 +1,46 @@
+// 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.
+
+#include "athena/wm/mru_window_tracker.h"
+
+#include "ui/aura/window.h"
+
+namespace athena {
+
+MruWindowTracker::MruWindowTracker(aura::Window* container)
+    : container_(container) {
+  container->AddObserver(this);
+}
+
+MruWindowTracker::~MruWindowTracker() {
+  if (container_)
+    container_->RemoveObserver(this);
+}
+
+aura::Window::Windows MruWindowTracker::GetWindowList() {
+  return aura::Window::Windows(mru_windows_.begin(), mru_windows_.end());
+}
+
+void MruWindowTracker::MoveToFront(aura::Window* window) {
+  DCHECK(window);
+  CHECK_EQ(container_, window->parent());
+  std::list<aura::Window*>::iterator it = std::find(
+      mru_windows_.begin(), mru_windows_.end(), window);
+  DCHECK(it != mru_windows_.end());
+  mru_windows_.erase(it);
+  mru_windows_.push_back(window);
+}
+
+// Overridden from WindowObserver:
+void MruWindowTracker::OnWillRemoveWindow(aura::Window* window) {
+  std::list<aura::Window*>::iterator it = std::find(
+      mru_windows_.begin(), mru_windows_.end(), window);
+  mru_windows_.erase(it);
+}
+
+void MruWindowTracker::OnWindowAdded(aura::Window* new_window) {
+  mru_windows_.push_back(new_window);
+}
+
+}  // namespace athena