Update shelf spacing in Chrome OS according to the MD specs

ash/common/system/tray/tray_constants.cc

 // Copyright (c) 2012 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/tray/tray_constants.h"
 
+#include "ash/common/material_design/material_design_controller.h"
+#include "base/logging.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace ash {
 
 const int kPaddingFromRightEdgeOfScreenBottomAlignment = 7;
 const int kPaddingFromBottomOfScreenBottomAlignment = 7;
 const int kPaddingFromOuterEdgeOfLauncherVerticalAlignment = 8;
 const int kPaddingFromInnerEdgeOfLauncherVerticalAlignment = 9;
 const int kPaddingFromBottomOfScreenVerticalAlignment = 10;
 
 // Padding used to position the system menu relative to the status area.
 const int kBubblePaddingHorizontalBottom = 6;
 const int kBubblePaddingHorizontalSide = 10;
 const int kBubblePaddingVerticalBottom = 3;
 const int kBubblePaddingVerticalSide = 15;
 
-const int kPaddingFromEdgeOfShelf = 3;
+// Padding used to adjust the size of status tray dark background.
+const int kAdjustBackgroundPadding = 3;
 
 // Top inset of system tray bubble for bottom anchor alignment.
 const int kTrayBubbleAnchorTopInsetBottomAnchor = 3;
 
 const int kTrayImageItemHorizontalPaddingBottomAlignment = 1;
 const int kTrayImageItemHorizontalPaddingVerticalAlignment = 1;
 const int kTrayImageItemVerticalPaddingVerticalAlignment = 1;
 
 // Size of tray items on the primary axis.
 const int kTrayItemSize = 32;
@@ skipping 39 matching lines @@
 const int kTrayPopupMaxWidth = 500;
 const int kNotificationIconWidth = 40;
 const int kNotificationButtonWidth = 32;
 const int kTrayNotificationContentsWidth = kTrayPopupMinWidth -
     (kNotificationIconWidth + kNotificationButtonWidth +
      (kTrayPopupPaddingHorizontal / 2) * 3);
 
 const int kTrayAvatarCornerRadius = 2;
 const int kTrayAvatarSize = 32;
 
-const int kTraySpacing = 4;
+const int kMessageCenterBubblePadding = 4;
 const int kShelfItemHeight = 38;
 
+// Items are 32 by 32 in the new Chrome OS MD requirements.
+const int kShelfItemSizeMD = 32;
+
+int GetTrayConstant(TrayConstant constant) {
+  const int kTraySpacing[] = {4, 8, 8};
+  const int kTrayPaddingFromEdgeOfShelf[] = {3, 8, 8};
+
+  const int mode = MaterialDesignController::GetMode();
+  DCHECK(mode >= MaterialDesignController::NON_MATERIAL &&
+         mode <= MaterialDesignController::MATERIAL_EXPERIMENTAL);
+
+  switch (constant) {
+    case TRAY_SPACING:
+      return kTraySpacing[mode];
+    case TRAY_PADDING_FROM_EDGE_OF_SHELF:
+      return kTrayPaddingFromEdgeOfShelf[mode];
+  }
+  NOTREACHED();
+  return 0;
+}
+
 }  // namespace ash