athena: Allow getting into split-view mode from overview-mode.

athena/wm/overview_toolbar.h

+// 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.
+
+#ifndef ATHENA_WM_OVERVIEW_TOOLBAR_H_
+#define ATHENA_WM_OVERVIEW_TOOLBAR_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace aura {
+class Window;
+}
+
+namespace gfx {
+class Transform;
+}
+
+namespace ui {
+class GestureEvent;
+}
+
+namespace athena {
+
+class ActionButton;
+
+// Responsible for showing action-buttons at the right edge of the screen during
+// overview mode.
+class OverviewToolbar {
+ public:
+  enum ActionType {
+    ACTION_TYPE_NONE,
+    ACTION_TYPE_CLOSE,
+    ACTION_TYPE_SPLIT,
+  };
+
+  explicit OverviewToolbar(aura::Window* container);
+  virtual ~OverviewToolbar();
+
+  ActionType current_action() const { return current_action_; }
+
+  // Returns the action the gesture-event is targeting.
+  ActionType GetHighlightAction(const ui::GestureEvent& event) const;
+
+  void SetHighlightAction(ActionType action);
+  void ShowActionButtons();
+  void HideActionButtons();
+
+ private:
+  void ToggleActionButtonsVisibility();
+  bool IsEventOverButton(ActionButton* button,
+                         const ui::GestureEvent& event) const;
+  gfx::Transform ComputeTransformFor(ActionButton* button) const;
+  void TransformButton(ActionButton* button);
+
+  bool shown_;
+  scoped_ptr<ActionButton> close_;
+  scoped_ptr<ActionButton> split_;
+  ActionType current_action_;
+  const gfx::Rect container_bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(OverviewToolbar);
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_WM_OVERVIEW_TOOLBAR_H_