Use overview mode for alt-tab cycling.

ash/wm/window_selector.cc

Index: ash/wm/window_selector.cc
diff --git a/ash/wm/window_selector.cc b/ash/wm/window_selector.cc
index f9de84c1019ea54e5f79025943effc5f193c84e2..d76eed521c7ab53bf7e064afc11d52495006ed8a 100644
--- a/ash/wm/window_selector.cc
+++ b/ash/wm/window_selector.cc
@@ -12,29 +12,271 @@
 #include "ash/wm/window_selector_delegate.h"
 #include "ash/wm/window_util.h"
 #include "base/memory/scoped_ptr.h"
+#include "third_party/skia/include/core/SkColor.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/base/events/event.h"
+#include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/display.h"
 #include "ui/gfx/interpolated_transform.h"
 #include "ui/gfx/transform_util.h"
+#include "ui/views/corewm/shadow_types.h"
 #include "ui/views/corewm/window_animations.h"
+#include "ui/views/corewm/window_util.h"
+#include "ui/views/widget/widget.h"
 
 namespace ash {
 
 namespace {
 
 const float kCardAspectRatio = 4.0f / 3.0f;
-const int kWindowMargin = 20;
+const int kWindowMargin = 30;
 const int kMinCardsMajor = 3;
 const int kOverviewTransitionMilliseconds = 100;
+const SkColor kWindowSelectorSelectionColor = SK_ColorBLACK;
+const float kWindowSelectorSelectionOpacity = 0.5f;
+const int kWindowSelectorSelectionPadding = 15;
 
-// Applies a transform to |window| to fit within |target_bounds| while
-// maintaining its aspect ratio.
-void TransformWindowToFitBounds(aura::Window* window,
-                                const gfx::Rect& target_bounds) {
-  const gfx::Rect bounds = window->bounds();
+// Creates a copy of |window| with |recreated_layer| in the |target_root|.
+views::Widget* CreateCopyOfWindow(aura::RootWindow* target_root,
+                                  aura::Window* src_window,
+                                  ui::Layer* recreated_layer) {
+  views::Widget* widget = new views::Widget;
+  views::Widget::InitParams params(views::Widget::InitParams::TYPE_POPUP);
+  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  params.parent = src_window->parent();
+  params.can_activate = false;
+  params.keep_on_top = true;
+  widget->set_focus_on_creation(false);
+  widget->Init(params);
+  widget->SetVisibilityChangedAnimationsEnabled(false);
+  widget->GetNativeWindow()->SetName("OverviewWindowCopy");

[Daniel Erat, 2013/08/09 20:54:35]

nit: include |src_window|'s id and/or name here?

[flackr, 2013/08/09 22:15:36]

Done.

+  views::corewm::SetShadowType(widget->GetNativeWindow(),
+                               views::corewm::SHADOW_TYPE_RECTANGULAR);
+
+  // Set the bounds in the target root window.
+  gfx::Display target_display =
+      Shell::GetScreen()->GetDisplayNearestWindow(target_root);
+  aura::client::ScreenPositionClient* screen_position_client =
+      aura::client::GetScreenPositionClient(src_window->GetRootWindow());
+  if (screen_position_client && target_display.is_valid()) {
+    screen_position_client->SetBounds(widget->GetNativeWindow(),
+        src_window->GetBoundsInScreen(), target_display);
+  } else {
+    widget->SetBounds(src_window->GetBoundsInScreen());
+  }
+  widget->StackAbove(src_window);
+
+  // Move the |recreated_layer| to the newly created window.
+  recreated_layer->set_delegate(src_window->layer()->delegate());
+  gfx::Rect layer_bounds = recreated_layer->bounds();
+  layer_bounds.set_origin(gfx::Point(0, 0));
+  recreated_layer->SetBounds(layer_bounds);
+  recreated_layer->SetVisible(false);
+  recreated_layer->parent()->Remove(recreated_layer);
+
+  aura::Window* window = widget->GetNativeWindow();
+  recreated_layer->SetVisible(true);
+  window->layer()->Add(recreated_layer);
+  window->layer()->StackAtTop(recreated_layer);
+  window->layer()->SetOpacity(1);
+  window->Show();
+  return widget;
+}
+
+// An observer which closes the widget and deletes the layer after an
+// animation finishes.
+class CleanupWidgetAfterAnimationObserver : public ui::LayerAnimationObserver {
+ public:
+  CleanupWidgetAfterAnimationObserver(views::Widget* widget, ui::Layer* layer);
+
+  virtual void OnLayerAnimationEnded(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationAborted(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationScheduled(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+
+ protected:
+  virtual ~CleanupWidgetAfterAnimationObserver();
+
+ private:
+  views::Widget* widget_;
+  ui::Layer* layer_;
+
+  DISALLOW_COPY_AND_ASSIGN(CleanupWidgetAfterAnimationObserver);
+};
+
+CleanupWidgetAfterAnimationObserver::CleanupWidgetAfterAnimationObserver(
+        views::Widget* widget,
+        ui::Layer* layer)
+    : widget_(widget),
+      layer_(layer) {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->AddObserver(this);
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationScheduled(
+    ui::LayerAnimationSequence* sequence) {
+}
+
+CleanupWidgetAfterAnimationObserver::~CleanupWidgetAfterAnimationObserver() {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->RemoveObserver(this);
+  widget_->Close();
+  widget_ = NULL;
+  if (layer_) {
+    views::corewm::DeepDeleteLayers(layer_);
+    layer_ = NULL;
+  }
+}
+
+// The animation settings used for window selector animations.
+class WindowSelectorAnimationSettings
+    : public ui::ScopedLayerAnimationSettings {
+ public:
+  WindowSelectorAnimationSettings(aura::Window* window) :
+      ui::ScopedLayerAnimationSettings(window->layer()->GetAnimator()) {
+    SetPreemptionStrategy(
+        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+    SetTransitionDuration(
+        base::TimeDelta::FromMilliseconds(kOverviewTransitionMilliseconds));
+  }
+
+  virtual ~WindowSelectorAnimationSettings() {
+  }
+};
+
+}  // namespace
+
+class WindowSelectorWindow {
+ public:
+  explicit WindowSelectorWindow(aura::Window* window);
+  virtual ~WindowSelectorWindow();
+
+  aura::Window* window() { return window_; }
+  const aura::Window* window() const { return window_; }
+
+  // Returns true if this window selector window contains the |target|. This is
+  // used to determine if an event targetted this window.
+  bool Contains(const aura::Window* target) const;
+
+  // Restores this window on exit rather than returning it to a minimized state
+  // if it was minimized on entering overview mode.
+  void RestoreWindowOnExit();
+
+  // Informs the WindowSelectorWindow that the window being watched was
+  // destroyed. This resets the internal window pointer to avoid calling
+  // anything on the window at destruction time.
+  void OnWindowDestroyed();
+
+  // Applies a transform to the window to fit within |target_bounds| while
+  // maintaining its aspect ratio.
+  void TransformToFitBounds(aura::RootWindow* root_window,
+                            const gfx::Rect& target_bounds);
+
+  gfx::Rect bounds() { return fit_bounds_; }
+
+ private:
+  // A weak pointer to the real window in the overview.
+  aura::Window* window_;
+
+  // A copy of the window used to transition the window to another root.
+  views::Widget* window_copy_;
+
+  // A weak pointer to a deep copy of the window's layers.
+  ui::Layer* layer_;
+
+  // If true, the window was minimized and should be restored if the window
+  // was not selected.
+  bool minimized_;
+
+  // The original transform of the window before entering overview mode.
+  gfx::Transform original_transform_;
+
+  // The bounds this window is fit to.
+  gfx::Rect fit_bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowSelectorWindow);
+};
+
+WindowSelectorWindow::WindowSelectorWindow(aura::Window* window)

[Daniel Erat, 2013/08/09 20:54:35]

doesn't need to happen here, but it'd probably be good for this to be moved into
a subdirectory under wm/ and split up into separate files for each of these
classes.

[flackr, 2013/08/09 22:15:36]

Added TODO.

+    : window_(window),
+      window_copy_(NULL),
+      layer_(NULL),
+      minimized_(window->GetProperty(aura::client::kShowStateKey) ==
+                 ui::SHOW_STATE_MINIMIZED),
+      original_transform_(window->layer()->transform()) {
+  if (minimized_)
+    window_->Show();
+}
+
+WindowSelectorWindow::~WindowSelectorWindow() {
+  if (window_) {
+    WindowSelectorAnimationSettings animation_settings(window_);
+    gfx::Transform transform;
+    window_->SetTransform(original_transform_);
+    if (minimized_) {
+      // Setting opacity 0 and visible false ensures that the property change
+      // to SHOW_STATE_MINIMIZED will not animate the window from its original
+      // bounds to the minimized position.
+      window_->layer()->SetOpacity(0);
+      window_->layer()->SetVisible(false);
+      window_->SetProperty(aura::client::kShowStateKey,
+                           ui::SHOW_STATE_MINIMIZED);
+    }
+  }
+  // If a copy of the window was created, clean it up.
+  if (window_copy_) {
+    if (window_) {
+      // If the initial window wasn't destroyed, the copy needs to be animated
+      // out. CleanupWidgetAfterAnimationObserver will destroy the widget and
+      // layer after the animation is complete.
+      new CleanupWidgetAfterAnimationObserver(window_copy_, layer_);
+      WindowSelectorAnimationSettings animation_settings(
+          window_copy_->GetNativeWindow());
+      window_copy_->GetNativeWindow()->SetTransform(original_transform_);
+    } else {
+      window_copy_->Close();
+      if (layer_)
+        views::corewm::DeepDeleteLayers(layer_);
+    }
+    window_copy_ = NULL;
+    layer_ = NULL;
+  }
+}
+
+bool WindowSelectorWindow::Contains(const aura::Window* window) const {
+  if (window_copy_ && window_copy_->GetNativeWindow()->Contains(window))
+    return true;
+  return window_->Contains(window);
+}
+
+void WindowSelectorWindow::RestoreWindowOnExit() {
+  minimized_ = false;
+  original_transform_ = gfx::Transform();
+}
+
+void WindowSelectorWindow::OnWindowDestroyed() {
+  window_ = NULL;
+}
+
+void WindowSelectorWindow::TransformToFitBounds(
+    aura::RootWindow* root_window,
+    const gfx::Rect& target_bounds) {
+  fit_bounds_ = target_bounds;
+  const gfx::Rect bounds = window_->GetBoundsInScreen();
   float scale = std::min(1.0f,
       std::min(static_cast<float>(target_bounds.width()) / bounds.width(),
                static_cast<float>(target_bounds.height()) / bounds.height()));
@@ -45,137 +287,185 @@ void TransformWindowToFitBounds(aura::Window* window,
   transform.Translate(target_bounds.x() - bounds.x() + offset.x(),
                       target_bounds.y() - bounds.y() + offset.y());
   transform.Scale(scale, scale);
-  // TODO(flackr): The window bounds or transform could change during overview
-  // mode. WindowSelector should create a copy of the window so that the
-  // displayed windows are not affected by changes happening in the background.
-  // This will be necessary for alt-tab cycling as well, as some windows will
-  // be coming from other displays: http://crbug.com/263481.
-  window->SetTransform(transform);
+  if (root_window != window_->GetRootWindow()) {
+    if (!window_copy_) {
+      layer_ = views::corewm::RecreateWindowLayers(window_, true);

[Daniel Erat, 2013/08/09 20:54:35]

nit: can you DCHECK(!layer_) and DCHECK(!window_copy_) here?

[flackr, 2013/08/09 22:15:36]

Added DCHECK(!layer_), I'm not sure I follow the DCHECK(!window_copy_), it may
already exist (and is checked for) if the layout is updating in response to a
deleted window.

[Daniel Erat, 2013/08/09 22:19:01]

whoops, sorry -- forget that part

+      window_copy_ = CreateCopyOfWindow(root_window, window_, layer_);
+    }
+    WindowSelectorAnimationSettings animation_settings(
+        window_copy_->GetNativeWindow());
+    window_copy_->GetNativeWindow()->SetTransform(transform);
+  }
+  WindowSelectorAnimationSettings animation_settings(window_);
+  window_->SetTransform(transform);
 }
 
-}  // namespace
+// A comparator for locating a given target window.
+struct WindowSelectorWindowComparator
+    : public std::unary_function<WindowSelectorWindow*, bool> {
+  explicit WindowSelectorWindowComparator(const aura::Window* target_window)
+      : target(target_window) {
+  }
+
+  bool operator() (const WindowSelectorWindow* window) const {

[Daniel Erat, 2013/08/09 20:54:35]

nit: remove space after operator()

[flackr, 2013/08/09 22:15:36]

Done.

+    return target == window->window();
+  }
+
+  const aura::Window* target;
+};
 
 WindowSelector::WindowSelector(const WindowList& windows,
+                               WindowSelector::Mode mode,
                                WindowSelectorDelegate* delegate)
-      : delegate_(delegate) {
+    : mode_(mode),
+      delegate_(delegate),
+      selected_window_(0),
+      selection_root_(NULL) {
   DCHECK(delegate_);
   for (size_t i = 0; i < windows.size(); ++i) {
     windows[i]->AddObserver(this);
-    WindowDetails details;
-    details.window = windows[i];
-    details.minimized = windows[i]->GetProperty(aura::client::kShowStateKey) ==
-                        ui::SHOW_STATE_MINIMIZED;
-    details.original_transform = windows[i]->layer()->transform();
-    if (details.minimized) {
-      windows[i]->Show();
-    }
-    windows_.push_back(details);
+    windows_.push_back(new WindowSelectorWindow(windows[i]));
   }
+  if (mode == WindowSelector::CYCLE)
+    selection_root_ = ash::Shell::GetActiveRootWindow();
   PositionWindows();
   ash::Shell::GetInstance()->AddPreTargetHandler(this);
 }
 
 WindowSelector::~WindowSelector() {
   for (size_t i = 0; i < windows_.size(); i++) {
-    ui::ScopedLayerAnimationSettings animation_settings(
-        windows_[i].window->layer()->GetAnimator());
-    animation_settings.SetPreemptionStrategy(
-        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
-    animation_settings.SetTransitionDuration(
-        base::TimeDelta::FromMilliseconds(kOverviewTransitionMilliseconds));
-    windows_[i].window->RemoveObserver(this);
-    gfx::Transform transform;
-    windows_[i].window->SetTransform(windows_[i].original_transform);
-    if (windows_[i].minimized) {
-      // Setting opacity 0 and visible false ensures that the property change
-      // to SHOW_STATE_MINIMIZED will not animate the window from its original
-      // bounds to the minimized position.
-      windows_[i].window->layer()->SetOpacity(0);
-      windows_[i].window->layer()->SetVisible(false);
-      windows_[i].window->SetProperty(aura::client::kShowStateKey,
-                                      ui::SHOW_STATE_MINIMIZED);
-    }
+    windows_[i]->window()->RemoveObserver(this);
   }
   ash::Shell::GetInstance()->RemovePreTargetHandler(this);
 }
 
+void WindowSelector::Step(WindowSelector::Direction direction) {
+  DCHECK(windows_.size() > 0);
+  if (!selection_widget_)
+    InitializeSelectionWidget();
+  selected_window_ = (selected_window_ + windows_.size() +
+      (direction == WindowSelector::FORWARD ? 1 : -1)) % windows_.size();
+  UpdateSelectionLocation(true);
+}
+
+void WindowSelector::SelectWindow() {
+  delegate_->OnWindowSelected(windows_[selected_window_]->window());
+}
+
 void WindowSelector::OnEvent(ui::Event* event) {
-  // TODO(flackr): This will prevent anything else from working while overview
-  // mode is active. This should only stop events from being sent to the windows
-  // in the overview but still allow interaction with the launcher / tray and
-  // hotkeys http://crbug.com/264289.
-  EventHandler::OnEvent(event);
-  event->StopPropagation();
+  ui::EventHandler::OnEvent(event);
+
+  // If the event is targetted at any of the windows in the overview, then
+  // prevent it from propagating.
+  aura::Window* target = static_cast<aura::Window*>(event->target());
+  for (size_t i = 0; i < windows_.size(); ++i) {
+    if (windows_[i]->Contains(target)) {
+      event->StopPropagation();
+      break;
+    }
+  }
 }
 
 void WindowSelector::OnMouseEvent(ui::MouseEvent* event) {
   if (event->type() != ui::ET_MOUSE_RELEASED)
     return;
-  aura::Window* target = static_cast<aura::Window*>(event->target());
-  if (!target->HitTest(event->location()))
+  WindowSelectorWindow* target = GetEventTarget(event);
+  if (!target)
     return;
 
-  HandleSelectionEvent(event);
+  HandleSelectionEvent(target);
 }
 
 void WindowSelector::OnGestureEvent(ui::GestureEvent* event) {
   if (event->type() != ui::ET_GESTURE_TAP)
     return;
-  HandleSelectionEvent(event);
+  WindowSelectorWindow* target = GetEventTarget(event);
+  if (!target)
+    return;
+
+  HandleSelectionEvent(target);
 }
 
 void WindowSelector::OnWindowDestroyed(aura::Window* window) {
-  std::vector<WindowDetails>::iterator iter =
-      std::find(windows_.begin(), windows_.end(), window);
+  ScopedVector<WindowSelectorWindow>::iterator iter =
+      std::find_if(windows_.begin(), windows_.end(),
+                   WindowSelectorWindowComparator(window));
   DCHECK(iter != windows_.end());
+  size_t deleted_index = iter - windows_.begin();
+  (*iter)->OnWindowDestroyed();
   windows_.erase(iter);
   if (windows_.empty()) {
     delegate_->OnSelectionCanceled();
     return;
   }
+  if (selected_window_ >= deleted_index) {
+    if (selected_window_ > deleted_index)
+      selected_window_--;
+    selected_window_ = selected_window_ % windows_.size();
+    UpdateSelectionLocation(true);
+  }
 
   PositionWindows();
 }
 
-void WindowSelector::HandleSelectionEvent(ui::Event* event) {
+WindowSelectorWindow* WindowSelector::GetEventTarget(ui::LocatedEvent* event) {
   aura::Window* target = static_cast<aura::Window*>(event->target());
+  // If the target window doesn't actually contain the event location (i.e.
+  // mouse down over the window and mouse up elsewhere) then do not select the
+  // window.
+  if (!target->HitTest(event->location()))
+    return NULL;
 
   for (size_t i = 0; i < windows_.size(); i++) {
-    if (windows_[i].window->Contains(target)) {
-      // The selected window should not be minimized when window selection is
-      // ended.
-      windows_[i].minimized = false;
-      windows_[i].original_transform = gfx::Transform();
-
-      // The delegate may delete the WindowSelector, assume the object may no
-      // longer valid after calling this.
-      delegate_->OnWindowSelected(windows_[i].window);
-      return;
-    }
+    if (windows_[i]->Contains(target))
+      return windows_[i];
   }
+  return NULL;
+}
+
+void WindowSelector::HandleSelectionEvent(WindowSelectorWindow* target) {
+  // The selected window should not be minimized when window selection is
+  // ended.
+  target->RestoreWindowOnExit();
+  delegate_->OnWindowSelected(target->window());
 }
 
 void WindowSelector::PositionWindows() {
-  Shell::RootWindowList root_window_list = Shell::GetAllRootWindows();
-  for (size_t i = 0; i < root_window_list.size(); ++i) {
-    PositionWindowsOnRoot(root_window_list[i]);
+  if (selection_root_) {  // mode == CYCLE

[Daniel Erat, 2013/08/09 20:54:35]

nit: is it worthwhile to add DCHECK_EQ(mode_, CYCLE) here and a similar OVERVIEW
DCHECK below?

[flackr, 2013/08/09 22:15:36]

Done.

+    std::vector<WindowSelectorWindow*> windows;
+    for (size_t i = 0; i < windows_.size(); ++i) {

[Daniel Erat, 2013/08/09 20:54:35]

nit: don't need curly braces here

[flackr, 2013/08/09 22:15:36]

Done.

+      windows.push_back(windows_[i]);
+    }
+    PositionWindowsOnRoot(selection_root_, windows);
+  } else {  // mode == OVERVIEW
+    Shell::RootWindowList root_window_list = Shell::GetAllRootWindows();
+    for (size_t i = 0; i < root_window_list.size(); ++i) {

[Daniel Erat, 2013/08/09 20:54:35]

nit: or here

[flackr, 2013/08/09 22:15:36]

Done.

+      PositionWindowsFromRoot(root_window_list[i]);
+    }
   }
 }
 
-void WindowSelector::PositionWindowsOnRoot(aura::RootWindow* root_window) {
-  gfx::Size window_size;
-  gfx::Rect total_bounds = ScreenAsh::GetDisplayWorkAreaBoundsInParent(
-      Shell::GetContainer(root_window,
-                          internal::kShellWindowId_DefaultContainer));
-
-  std::vector<WindowDetails> windows;
+void WindowSelector::PositionWindowsFromRoot(aura::RootWindow* root_window) {
+  std::vector<WindowSelectorWindow*> windows;
   for (size_t i = 0; i < windows_.size(); ++i) {
-    if (windows_[i].window->GetRootWindow() == root_window)
+    if (windows_[i]->window()->GetRootWindow() == root_window)
       windows.push_back(windows_[i]);
   }
+  PositionWindowsOnRoot(root_window, windows);
+}
+
+void WindowSelector::PositionWindowsOnRoot(
+    aura::RootWindow* root_window,
+    const std::vector<WindowSelectorWindow*>& windows) {
   if (windows.empty())
     return;
 
+  gfx::Size window_size;
+  gfx::Rect total_bounds = ScreenAsh::ConvertRectToScreen(root_window,
+      ScreenAsh::GetDisplayWorkAreaBoundsInParent(
+      Shell::GetContainer(root_window,
+                          internal::kShellWindowId_DefaultContainer)));
+
   // Find the minimum number of windows per row that will fit all of the
   // windows on screen.
   size_t columns = std::max(
@@ -195,12 +485,6 @@ void WindowSelector::PositionWindowsOnRoot(aura::RootWindow* root_window) {
   int y_offset = total_bounds.y() + (total_bounds.height() -
       rows * window_size.height()) / 2;
   for (size_t i = 0; i < windows.size(); ++i) {
-    ui::ScopedLayerAnimationSettings animation_settings(
-        windows[i].window->layer()->GetAnimator());
-    animation_settings.SetPreemptionStrategy(
-        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
-    animation_settings.SetTransitionDuration(
-        base::TimeDelta::FromMilliseconds(kOverviewTransitionMilliseconds));
     gfx::Transform transform;
     int column = i % columns;
     int row = i / columns;
@@ -209,7 +493,48 @@ void WindowSelector::PositionWindowsOnRoot(aura::RootWindow* root_window) {
                             window_size.width(),
                             window_size.height());
     target_bounds.Inset(kWindowMargin, kWindowMargin);
-    TransformWindowToFitBounds(windows[i].window, target_bounds);
+    windows[i]->TransformToFitBounds(root_window, target_bounds);
+  }
+}
+
+void WindowSelector::InitializeSelectionWidget() {
+  selection_widget_.reset(new views::Widget);
+  views::Widget::InitParams params;
+  params.type = views::Widget::InitParams::TYPE_POPUP;
+  params.can_activate = false;
+  params.keep_on_top = false;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  params.opacity = views::Widget::InitParams::OPAQUE_WINDOW;
+  params.parent = Shell::GetContainer(
+      selection_root_,
+      internal::kShellWindowId_DefaultContainer);
+  params.accept_events = false;
+  selection_widget_->set_focus_on_creation(false);
+  selection_widget_->Init(params);
+  views::View* content_view = new views::View;
+  content_view->set_background(
+      views::Background::CreateSolidBackground(kWindowSelectorSelectionColor));
+  selection_widget_->SetContentsView(content_view);
+  UpdateSelectionLocation(false);
+  selection_widget_->GetNativeWindow()->parent()->StackChildAtBottom(
+      selection_widget_->GetNativeWindow());
+  selection_widget_->Show();
+  selection_widget_->GetNativeWindow()->layer()->SetOpacity(
+      kWindowSelectorSelectionOpacity);
+}
+
+void WindowSelector::UpdateSelectionLocation(bool animate) {
+  if (!selection_widget_)
+    return;
+  gfx::Rect target_bounds = windows_[selected_window_]->bounds();
+  target_bounds.Inset(-kWindowSelectorSelectionPadding,
+                      -kWindowSelectorSelectionPadding);
+  if (animate) {
+    WindowSelectorAnimationSettings animation_settings(
+        selection_widget_->GetNativeWindow());
+    selection_widget_->SetBounds(target_bounds);
+  } else {
+    selection_widget_->SetBounds(target_bounds);
   }
 }