Add panels as a single group of windows per display for overview window cycling.

ash/wm/overview/scoped_transform_overview_window.h

Index: ash/wm/overview/scoped_transform_overview_window.h
diff --git a/ash/wm/overview/scoped_transform_overview_window.h b/ash/wm/overview/scoped_transform_overview_window.h
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+++ b/ash/wm/overview/scoped_transform_overview_window.h
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+// Copyright 2013 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.
+
+#ifndef ASH_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_
+#define ASH_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_
+
+#include "base/compiler_specific.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/transform.h"
+
+namespace aura {
+class RootWindow;
+class Window;
+}
+
+namespace ui {
+class Layer;
+}
+
+namespace views {
+class Widget;
+}
+
+namespace ash {
+
+// Manages a window in the overview mode. This class allows transforming the
+// window with a helper to determine the best fit in certain bounds and
+// copies the window if being moved to another display. The window's state is
+// restored on destruction of this object.
+class ScopedTransformOverviewWindow {
+ public:
+  // The duration of transitions used for window transforms.
+  static const int kTransitionMilliseconds;
+
+  // Returns the transform necessary to fit |rect| into |bounds| preserving
+  // aspect ratio and centering.
+  static gfx::Transform GetTransformForRectPreservingAspectRatio(
+      const gfx::Rect& rect,
+      const gfx::Rect& bounds);
+
+  explicit ScopedTransformOverviewWindow(aura::Window* window);
+  virtual ~ScopedTransformOverviewWindow();
+
+  // 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 the window if it was minimized.
+  void RestoreWindow();
+
+  // 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 ScopedTransformOverviewWindow 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();
+
+  // Sets |transform| on the window and a copy of the window if the target
+  // |root_window| is not the window's root window.
+  void SetTransform(aura::RootWindow* root_window,
+                    const gfx::Transform& transform);
+
+  aura::Window* window() const { return window_; }
+
+ protected:
+  // Dispatched when the overview of this window has started.
+  virtual void OnOverviewStarted();
+
+ 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_;
+
+  // True if the window has been transformed for overview mode.
+  bool overview_started_;
+
+  // The original transform of the window before entering overview mode.
+  gfx::Transform original_transform_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedTransformOverviewWindow);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_