Review fixes.

base/base_tests/geo_object_id_tests.cpp

@@ -8,6 +8,7 @@ UNIT_TEST(GeoObjectId)
 {
   GeoObjectId const invalid(GeoObjectId::kInvalid);
   TEST_EQUAL(invalid.GetType(), GeoObjectId::Type::Invalid, ());
+  TEST_EQUAL(DebugPrint(invalid), "Invalid 0", ());
 
   GeoObjectId const node(GeoObjectId::Type::ObsoleteOsmNode, 12345);
   TEST_EQUAL(node.GetSerialId(), 12345ULL, ());
@@ -41,13 +42,4 @@ UNIT_TEST(GeoObjectId)
   TEST_EQUAL(fias.GetType(), GeoObjectId::Type::Fias, ());
   TEST_EQUAL(DebugPrint(fias), "FIAS 61861", ());
 }
-
-UNIT_TEST(GeoObjectId_DebugPrint)
-{
-  GeoObjectId const invalid;
-  TEST_EQUAL(DebugPrint(invalid), "Invalid 0", ());
-
-  GeoObjectId const valid(GeoObjectId::Type::OsmWay, 123);
-  TEST_EQUAL(DebugPrint(valid), "Osm Way 123", ());
-}
 }  // namespace base

base/geo_object_id.cpp

@@ -89,10 +89,8 @@ std::string DebugPrint(GeoObjectId::Type const & t)
 std::string DebugPrint(GeoObjectId const & id)
 {
   std::ostringstream oss;
-  // To print serial id it's written |id.m_encodedId & kSerialMask| instead of id.GetSerialId().
-  // It's done to be able to print a instance of GeoObjectId created by default constructor.
-  // In case of instance of GeoObjectId created by default ctor GetSerialId() shouldn't be called.
-  oss << DebugPrint(id.GetType()) << " " << (id.m_encodedId & kSerialMask);
+  // GetSerialId() does not work for invalid ids but we may still want to print them.
+  oss << DebugPrint(id.GetType()) << " " << (id.GetEncodedId() & kSerialMask);
   return oss.str();
 }
 }  // namespace base

base/geo_object_id.hpp

@@ -35,8 +35,6 @@ namespace base
 // and the difference does not seem important. Also this would probably touch the highest bit.
 class GeoObjectId
 {
-  friend std::string DebugPrint(GeoObjectId const & id);
-
 public:
   // Sources of the objects.
   enum class Type : uint8_t