New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/drape_frontend/animation/interpolation_holder.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "base/macros.hpp"
+
+#include <set>
+
+namespace df
+{
+class BaseInterpolator;
+
+class InterpolationHolder
+{
+public:
+  static InterpolationHolder & Instance();
+  bool IsActive() const;
+  void Advance(double elapsedSeconds);
+
+private:
+  InterpolationHolder() = default;
+  ~InterpolationHolder();
+  DISALLOW_COPY_AND_MOVE(InterpolationHolder);
+
+private:
+  friend class BaseInterpolator;
+  void RegisterInterpolator(BaseInterpolator * interpolator);
+  void DeregisterInterpolator(BaseInterpolator * interpolator);
+
+  using TInterpolatorSet = std::set<BaseInterpolator *>;
+  TInterpolatorSet m_interpolations;
+};
+}  // namespace df