Use anonymous namespace for constants

src/context/contextview.cpp

@@ -65,7 +65,9 @@
 #include "contextview.h"
 #include "contextalbum.h"
 
-const int ContextView::kWidgetSpacing = 50;
+namespace {
+constexpr int kWidgetSpacing = 50;
+}
 
 ContextView::ContextView(QWidget *parent)
     : QWidget(parent),

src/context/contextview.h

@@ -101,8 +101,6 @@ class ContextView : public QWidget {
   void AlbumCoverLoaded(const Song &song, const QImage &image);
 
  private:
-  static const int kWidgetSpacing;
-
   Application *app_;
   CollectionView *collectionview_;
   AlbumCoverChoiceController *album_cover_choice_controller_;