Give Ash material design tray items the correct size and layout

ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc

Index: ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc
diff --git a/ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc b/ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc
index b32dd66b9ef361932a5929f640a23fe6ec674e20..63ebe435b04104dce8af24de793c58dfb511af6a 100644
--- a/ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc
+++ b/ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc
@@ -63,18 +63,22 @@ void VirtualKeyboardTray::SetShelfAlignment(ShelfAlignment alignment) {
   // Pad button size to align with other controls in the system tray.
   const gfx::ImageSkia image =
       button_->GetImage(views::CustomButton::STATE_NORMAL);
-  int top_padding = (kTrayBarButtonWidth - image.height()) / 2;
-  int left_padding = (kTrayBarButtonWidth - image.width()) / 2;
-  int bottom_padding = kTrayBarButtonWidth - image.height() - top_padding;
-  int right_padding = kTrayBarButtonWidth - image.width() - left_padding;
-
-  // Square up the padding if horizontally aligned. Avoid extra padding when
-  // vertically aligned as the button would violate the width constraint on the
-  // shelf.
-  if (IsHorizontalAlignment(alignment)) {
-    int additional_padding = std::max(0, top_padding - left_padding);
-    left_padding += additional_padding;
-    right_padding += additional_padding;
+  const int size = GetTrayConstant(VIRTUAL_KEYBOARD_BUTTON_SIZE);
+
+  const int top_padding = (size - image.height()) / 2;
+  int left_padding = (size - image.width()) / 2;
+  const int bottom_padding = size - image.height() - top_padding;

[yiyix, 2016/06/27 18:39:43]

size - image.height() - top_padding = (size - image.height()) / 2
may be use the later one for less computation?

[tdanderson, 2016/06/27 21:29:42]

Thanks for the suggestion - I can actually do one better than this since it
works out that bottom_padding = top_padding :) This looks a lot nicer in the
next patch set.

Changed here and in overview_button_tray

+  int right_padding = size - image.width() - left_padding;
+
+  if (!ash::MaterialDesignController::IsShelfMaterial()) {
+    // Square up the padding if horizontally aligned. Avoid extra padding when
+    // vertically aligned as the button would violate the width constraint on
+    // the shelf.
+    if (IsHorizontalAlignment(alignment)) {
+      int additional_padding = std::max(0, top_padding - left_padding);
+      left_padding += additional_padding;
+      right_padding += additional_padding;
+    }
   }
 
   button_->SetBorder(views::Border::CreateEmptyBorder(