Add cairo interface.

src/graphics/DrawingContext.cpp

@@ -0,0 +1,18 @@
+#include "DrawingContext.h"
+
+#include "INativeDrawingContext.h"
+
+std::unique_ptr<DrawingContext> DrawingContext::Create()
+{
+    return std::make_unique<DrawingContext>();
+}
+
+void DrawingContext::SetNativeContext(std::unique_ptr<INativeDrawingContext> context)
+{
+    mNativeDrawingContext = std::move(context);
+}
+
+INativeDrawingContext* DrawingContext::GetNativeContext()
+{
+    return mNativeDrawingContext.get();
+}