Fix VirtualKeyboardTray border

ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc

 // 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.
 
 #include "ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_tray.h"
 
 #include <algorithm>
 
 #include "ash/common/keyboard/keyboard_ui.h"
 #include "ash/common/material_design/material_design_controller.h"
@@ skipping 80 matching lines @@
     UnobserveKeyboardController();
   }
 }
 
 void VirtualKeyboardTray::OnKeyboardBoundsChanging(
     const gfx::Rect& new_bounds) {
   SetDrawBackgroundAsActive(!new_bounds.IsEmpty());
 }
 
 void VirtualKeyboardTray::SetIconBorderForShelfAlignment() {
+  tray_container()->SetBorder(views::Border::NullBorder());

[James Cook, 2016/08/09 15:54:32]

Why does this have to be done every time the shelf alignment changes? If it
can't just be done once, can you add a comment here explaining why it has to be
done each time?

[mohsen, 2016/08/09 16:32:51]

After each shelf alignment change, the border is reset (see
StatusAreaWidgetDelegate::SetBorderOnChild()). Added a comment.

+
   const gfx::ImageSkia& image = icon_->GetImage();
   const int size = GetTrayConstant(VIRTUAL_KEYBOARD_BUTTON_SIZE);
   const int vertical_padding = (size - image.height()) / 2;
   int horizontal_padding = (size - image.width()) / 2;
   if (!ash::MaterialDesignController::IsShelfMaterial() &&
       IsHorizontalAlignment(shelf_alignment())) {
     // Square up the padding if horizontally aligned. Avoid extra padding when
     // vertically aligned as the button would violate the width constraint on
     // the shelf.
     horizontal_padding += std::max(0, vertical_padding - horizontal_padding);
@@ skipping 10 matching lines @@
 }
 
 void VirtualKeyboardTray::UnobserveKeyboardController() {
   keyboard::KeyboardController* keyboard_controller =
       keyboard::KeyboardController::GetInstance();
   if (keyboard_controller)
     keyboard_controller->RemoveObserver(this);
 }
 
 }  // namespace ash