Refactor most recently used window tracking into a separate class.

ash/wm/window_cycle_controller.cc

Index: ash/wm/window_cycle_controller.cc
diff --git a/ash/wm/window_cycle_controller.cc b/ash/wm/window_cycle_controller.cc
index 89af6c1836f8548ee56c5c4ded9f0eed40dabd9c..413d0da958d9d4e26c9cc79c7d5c026f63985a3c 100644
--- a/ash/wm/window_cycle_controller.cc
+++ b/ash/wm/window_cycle_controller.cc
@@ -9,7 +9,7 @@
 #include "ash/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
-#include "ash/wm/activation_controller.h"
+#include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/window_cycle_list.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace_controller.h"
@@ -21,12 +21,6 @@ namespace ash {
 
 namespace {
 
-// List of containers whose children we will cycle through.
-const int kContainerIds[] = {
-  internal::kShellWindowId_DefaultContainer,
-  internal::kShellWindowId_AlwaysOnTopContainer
-};
-
 // Filter to watch for the termination of a keyboard gesture to cycle through
 // multiple windows.
 class WindowCycleEventFilter : public ui::EventHandler {
@@ -56,65 +50,15 @@ void WindowCycleEventFilter::OnKeyEvent(ui::KeyEvent* event) {
   }
 }
 
-// Adds all the children of |window| to |windows|.
-void AddAllChildren(aura::Window* window,
-                    WindowCycleList::WindowList* windows) {
-  const WindowCycleList::WindowList& children(window->children());
-  windows->insert(windows->end(), children.begin(), children.end());
-}
-
-// Adds all the children of all of |window|s children to |windows|.
-void AddWorkspaceChildren(aura::Window* window,
-                          WindowCycleList::WindowList* windows) {
-  for (size_t i = 0; i < window->children().size(); ++i)
-    AddAllChildren(window->children()[i], windows);
-}
-
-// Adds the windows that can be cycled through for the specified window id to
-// |windows|.
-void AddCycleWindows(aura::RootWindow* root,
-                     int container_id,
-                     WindowCycleList::WindowList* windows) {
-  aura::Window* container = Shell::GetContainer(root, container_id);
-  if (container_id == internal::kShellWindowId_DefaultContainer)
-    AddWorkspaceChildren(container, windows);
-  else
-    AddAllChildren(container, windows);
-}
-
 }  // namespace
 
 //////////////////////////////////////////////////////////////////////////////
 // WindowCycleController, public:
 
-WindowCycleController::WindowCycleController(
-    aura::client::ActivationClient* activation_client)
-    : activation_client_(activation_client) {
-  activation_client_->AddObserver(this);
+WindowCycleController::WindowCycleController() {
 }
 
 WindowCycleController::~WindowCycleController() {
-  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
-  for (Shell::RootWindowList::const_iterator iter = root_windows.begin();
-       iter != root_windows.end(); ++iter) {
-    for (size_t i = 0; i < arraysize(kContainerIds); ++i) {
-      aura::Window* container = Shell::GetContainer(*iter, kContainerIds[i]);
-      if (container)
-        container->RemoveObserver(this);
-    }
-    aura::Window* default_container =
-        Shell::GetContainer(*iter, internal::kShellWindowId_DefaultContainer);
-    if (default_container) {
-      for (size_t i = 0; i < default_container->children().size(); ++i) {
-        aura::Window* workspace_window = default_container->children()[i];
-        DCHECK_EQ(internal::kShellWindowId_WorkspaceContainer,
-                  workspace_window->id());
-        workspace_window->RemoveObserver(this);
-      }
-    }
-  }
-
-  activation_client_->RemoveObserver(this);
   StopCycling();
 }
 
@@ -156,7 +100,7 @@ void WindowCycleController::HandleLinearCycleWindow() {
 
   // Use the reversed list of windows to prevent a 2-cycle of the most recent
   // windows occurring.
-  WindowCycleList cycle_list(BuildWindowList(NULL,true));
+  WindowCycleList cycle_list(MruWindowTracker::BuildWindowList(true));
   cycle_list.Step(WindowCycleList::FORWARD);
 }
 
@@ -164,81 +108,12 @@ void WindowCycleController::AltKeyReleased() {
   StopCycling();
 }
 
-// static
-std::vector<aura::Window*> WindowCycleController::BuildWindowList(
-    const std::list<aura::Window*>* mru_windows,
-    bool top_most_at_end) {
-  WindowCycleList::WindowList windows;
-  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
-
-  aura::RootWindow* active_root = Shell::GetActiveRootWindow();
-  for (Shell::RootWindowList::const_iterator iter = root_windows.begin();
-       iter != root_windows.end(); ++iter) {
-    if (*iter == active_root)
-      continue;
-    for (size_t i = 0; i < arraysize(kContainerIds); ++i)
-      AddCycleWindows(*iter, kContainerIds[i], &windows);
-  }
-
-  // Add windows in the active root windows last so that the topmost window
-  // in the active root window becomes the front of the list.
-  for (size_t i = 0; i < arraysize(kContainerIds); ++i)
-    AddCycleWindows(active_root, kContainerIds[i], &windows);
-
-  // Removes unfocusable windows.
-  WindowCycleList::WindowList::iterator last =
-      std::remove_if(
-          windows.begin(),
-          windows.end(),
-          std::not1(std::ptr_fun(ash::wm::CanActivateWindow)));
-  windows.erase(last, windows.end());
-
-  // Put the windows in the mru_windows list at the head, if it's available.
-  if (mru_windows) {
-    // Iterate through the list backwards, so that we can move each window to
-    // the front of the windows list as we find them.
-    for (std::list<aura::Window*>::const_reverse_iterator ix =
-         mru_windows->rbegin();
-         ix != mru_windows->rend(); ++ix) {
-      WindowCycleList::WindowList::iterator window =
-          std::find(windows.begin(), windows.end(), *ix);
-      if (window != windows.end()) {
-        windows.erase(window);
-        windows.push_back(*ix);
-      }
-    }
-  }
-
-  // Window cycling expects the topmost window at the front of the list.
-  if (!top_most_at_end)
-    std::reverse(windows.begin(), windows.end());
-
-  return windows;
-}
-
-void WindowCycleController::OnRootWindowAdded(aura::RootWindow* root_window) {
-  for (size_t i = 0; i < arraysize(kContainerIds); ++i) {
-    aura::Window* container =
-        Shell::GetContainer(root_window, kContainerIds[i]);
-    container->AddObserver(this);
-  }
-
-  aura::Window* default_container =
-      Shell::GetContainer(root_window,
-                          internal::kShellWindowId_DefaultContainer);
-  for (size_t i = 0; i < default_container->children().size(); ++i) {
-    aura::Window* workspace_window = default_container->children()[i];
-    DCHECK_EQ(internal::kShellWindowId_WorkspaceContainer,
-              workspace_window->id());
-    workspace_window->AddObserver(this);
-  }
-}
-
 //////////////////////////////////////////////////////////////////////////////
 // WindowCycleController, private:
 
 void WindowCycleController::StartCycling() {
-  windows_.reset(new WindowCycleList(BuildWindowList(&mru_windows_, false)));
+  windows_.reset(new WindowCycleList(ash::Shell::GetInstance()->
+      mru_window_tracker()->BuildMruWindowList()));
 }
 
 void WindowCycleController::Step(Direction direction) {
@@ -254,23 +129,6 @@ void WindowCycleController::StopCycling() {
     Shell::GetInstance()->RemovePreTargetHandler(event_handler_.get());
     event_handler_.reset();
   }
-
-  // Add the currently focused window to the MRU list
-  aura::Window* active_window = wm::GetActiveWindow();
-  mru_windows_.remove(active_window);
-  mru_windows_.push_front(active_window);
-}
-
-// static
-bool WindowCycleController::IsTrackedContainer(aura::Window* window) {
-  if (!window)
-    return false;
-  for (size_t i = 0; i < arraysize(kContainerIds); ++i) {
-    if (window->id() == kContainerIds[i]) {
-      return true;
-    }
-  }
-  return window->id() == internal::kShellWindowId_WorkspaceContainer;
 }
 
 void WindowCycleController::InstallEventFilter() {
@@ -278,28 +136,4 @@ void WindowCycleController::InstallEventFilter() {
   Shell::GetInstance()->AddPreTargetHandler(event_handler_.get());
 }
 
-void WindowCycleController::OnWindowActivated(aura::Window* gained_active,
-                                              aura::Window* lost_active) {
-  if (gained_active && !IsCycling() &&
-      IsTrackedContainer(gained_active->parent())) {
-    mru_windows_.remove(gained_active);
-    mru_windows_.push_front(gained_active);
-  }
-}
-
-void WindowCycleController::OnWindowAdded(aura::Window* window) {
-  if (window->id() == internal::kShellWindowId_WorkspaceContainer)
-    window->AddObserver(this);
-}
-
-void WindowCycleController::OnWillRemoveWindow(aura::Window* window) {
-  mru_windows_.remove(window);
-  if (window->id() == internal::kShellWindowId_WorkspaceContainer)
-    window->RemoveObserver(this);
-}
-
-void WindowCycleController::OnWindowDestroying(aura::Window* window) {
-  window->RemoveObserver(this);
-}
-
 }  // namespace ash