Add palette tray to ash.

ash/common/system/chromeos/palette/palette_tray.h

Index: ash/common/system/chromeos/palette/palette_tray.h
diff --git a/ash/common/system/chromeos/palette/palette_tray.h b/ash/common/system/chromeos/palette/palette_tray.h
new file mode 100644
index 0000000000000000000000000000000000000000..3c648fe2b9166d65b8e28952e72659e6ee1af56c
--- /dev/null
+++ b/ash/common/system/chromeos/palette/palette_tray.h
@@ -0,0 +1,87 @@
+// Copyright 2016 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_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_BUTTON_TRAY_H_
+#define ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_BUTTON_TRAY_H_
+
+#include <map>
+#include <memory>
+
+#include "ash/ash_export.h"
+#include "ash/common/session/session_state_observer.h"
+#include "ash/common/shell_observer.h"
+#include "ash/common/system/tray/tray_background_view.h"
+#include "base/macros.h"
+
+namespace views {
+class ImageView;
+class Widget;
+}
+
+namespace ash {
+
+class TrayBubbleWrapper;
+class PaletteToolManager;
+
+class ASH_EXPORT PaletteTray : public TrayBackgroundView,
+                               public SessionStateObserver,
+                               public ShellObserver,
+                               public views::TrayBubbleView::Delegate {
+ public:
+  explicit PaletteTray(WmShelf* wm_shelf);
+  ~PaletteTray() override;
+
+  // ActionableView:
+  bool PerformAction(const ui::Event& event) override;
+
+  // SessionStateObserver:
+  void SessionStateChanged(SessionStateDelegate::SessionState state) override;
+
+  // TrayBackgroundView:
+  void ClickedOutsideBubble() override;
+  base::string16 GetAccessibleNameForTray() override;
+  void HideBubbleWithView(const views::TrayBubbleView* bubble_view) override;
+  void SetShelfAlignment(ShelfAlignment alignment) override;
+  void AnchorUpdated() override;
+
+ private:
+  // views::TrayBubbleView::Delegate:
+  void BubbleViewDestroyed() override;
+  void OnMouseEnteredView() override;
+  void OnMouseExitedView() override;
+  base::string16 GetAccessibleNameForBubble() override;
+  gfx::Rect GetAnchorRect(views::Widget* anchor_widget,
+                          AnchorType anchor_type,
+                          AnchorAlignment anchor_alignment) const override;
+  void OnBeforeBubbleWidgetInit(
+      views::Widget* anchor_widget,
+      views::Widget* bubble_widget,
+      views::Widget::InitParams* params) const override;
+  void HideBubble(const views::TrayBubbleView* bubble_view) override;
+
+  // Creates a new border for the icon. The padding is determined based on the
+  // alignment of the shelf.
+  void SetIconBorderForShelfAlignment();
+
+  // Updates the tray icon from the palette tool manager.
+  void UpdateTrayIcon();
+
+  // Sets the icon to visible if the palette can be used.
+  void UpdateIconVisibility();
+
+  bool OpenBubble();
+  void AddToolsToView(views::View* host);
+
+  std::unique_ptr<PaletteToolManager> palette_tool_manager_;
+  std::unique_ptr<TrayBubbleWrapper> bubble_;
+
+  // Weak pointer, will be parented by TrayContainer for its lifetime.
+  views::ImageView* icon_;
+
+  DISALLOW_COPY_AND_ASSIGN(PaletteTray);
+};
+
+}  // namespace ash
+
+#endif  // ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_BUTTON_TRAY_H_