Give Ash material design tray items the correct size and layout

ash/shelf/app_list_button.cc

Index: ash/shelf/app_list_button.cc
diff --git a/ash/shelf/app_list_button.cc b/ash/shelf/app_list_button.cc
index 1fb50398c101db0230bfe64aa0f319a58a00e72f..df42c709ecc5ffcbf918b72640ff37a4e0cb053e 100644
--- a/ash/shelf/app_list_button.cc
+++ b/ash/shelf/app_list_button.cc
@@ -10,6 +10,7 @@
 #include "ash/common/shelf/shelf_item_types.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/common/shelf/wm_shelf_util.h"
+#include "ash/common/system/tray/tray_constants.h"
 #include "ash/shelf/ink_drop_button_listener.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_view.h"
@@ -30,9 +31,6 @@
 
 namespace ash {
 
-// Radius of the app list button circular background.
-const int kAppListButtonBackgroundRadius = 16;
-
 AppListButton::AppListButton(InkDropButtonListener* listener,
                              ShelfView* shelf_view)
     : views::ImageButton(nullptr),
@@ -143,12 +141,11 @@ void AppListButton::PaintBackgroundMD(gfx::Canvas* canvas) {
   }
 
   // Paint the circular background of AppList button.
+  const int kRadius = kTrayItemSize / 2;

[James Cook, 2016/06/27 18:04:12]

nit: elsewhere you use the style "const int radius =". Either is fine, but be
consistent.

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

Done.

   gfx::Point circle_center = GetContentsBounds().CenterPoint();
   if (!IsHorizontalAlignment(shelf_view_->shelf()->alignment()))
     circle_center = gfx::Point(circle_center.y(), circle_center.x());
-
-  canvas->DrawCircle(circle_center, kAppListButtonBackgroundRadius,
-                     background_paint);
+  canvas->DrawCircle(circle_center, kRadius, background_paint);
 
   if (Shell::GetInstance()->GetAppListTargetVisibility() ||
       draw_background_as_active_) {
@@ -156,9 +153,7 @@ void AppListButton::PaintBackgroundMD(gfx::Canvas* canvas) {
     highlight_paint.setColor(kShelfButtonActivatedHighlightColor);
     highlight_paint.setFlags(SkPaint::kAntiAlias_Flag);
     highlight_paint.setStyle(SkPaint::kFill_Style);
-
-    canvas->DrawCircle(circle_center, kAppListButtonBackgroundRadius,
-                       highlight_paint);
+    canvas->DrawCircle(circle_center, kRadius, highlight_paint);
   }
 }