Remove TransparentActivateWindowButton from Overview Mode

ash/wm/overview/overview_window_button.h

Index: ash/wm/overview/overview_window_button.h
diff --git a/ash/wm/overview/overview_window_button.h b/ash/wm/overview/overview_window_button.h
new file mode 100644
index 0000000000000000000000000000000000000000..d1dbd6df9e3f348d1842831baa400cf2f1541fee
--- /dev/null
+++ b/ash/wm/overview/overview_window_button.h
@@ -0,0 +1,70 @@
+// Copyright 2015 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_OVERVIEW_WINDOW_BUTTON_H_
+#define ASH_WM_OVERVIEW_OVERVIEW_WINDOW_BUTTON_H_
+
+#include "ash/wm/overview/scoped_transform_overview_window.h"
+#include "ui/views/controls/button/button.h"
+
+namespace aura {
+class ScopedWindowTargeter;
+}
+
+namespace ash {
+
+class OverviewWindowTargeter;
+
+// A class that encapsulates the LabelButton and targeting logic for overview
+// mode.
+class OverviewWindowButton : public views::ButtonListener {
+ public:
+  explicit OverviewWindowButton(aura::Window* target);

[flackr, 2015/01/23 19:31:55]

nit: brief description. I.e. what is |target|.

[Nina, 2015/01/23 20:35:54]

Done.

+
+  ~OverviewWindowButton() override;
+
+  // Sets the label and targetable bounds.
+  void SetBounds(const gfx::Rect& bounds,
+                 const OverviewAnimationType& animation_type);
+
+  // Sends an a11y focus alert so that, if chromevox is enabled, the window
+  // label is read.
+  void SendFocusAlert() const;
+
+  // Sets the label text.
+  void SetLabelText(const base::string16& title);
+
+  // Sets the label opacity.
+  void SetOpacity(float opacity);
+
+  // views::ButtonListener
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+
+ private:
+  friend class WindowSelectorTest;
+
+  // LabelButton shown under each of the windows.
+  class OverviewButtonView;
+
+  // Window that the button will activate on click.
+  aura::Window* target_;
+
+  // Label under the window displaying its active tab name.
+  scoped_ptr<views::Widget> window_label_;
+
+  // View for the label button under the window.
+  OverviewButtonView* window_label_button_view_;
+
+  // Reference to the targeter implemented by the scoped window targeter.
+  OverviewWindowTargeter* overview_window_targeter_;
+
+  // Stores and restores on exit the actual window targeter.
+  scoped_ptr<aura::ScopedWindowTargeter> scoped_window_targeter_;
+
+  DISALLOW_COPY_AND_ASSIGN(OverviewWindowButton);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_OVERVIEW_OVERVIEW_WINDOW_BUTTON_H_