Update overworld loading logic to use Rom pointers directly; adjust test cases for consistency.

test/CMakeLists.txt

@@ -16,9 +16,9 @@ add_executable(
   yaze_test
   yaze_test.cc
   rom_test.cc
+  test_editor.cc
   gfx/compression_test.cc
   gfx/snes_palette_test.cc
-  integration/test_editor.cc
   zelda3/message_test.cc
   zelda3/overworld_test.cc
   zelda3/sprite_builder_test.cc

test/zelda3/overworld_test.cc

@@ -20,12 +20,12 @@ class OverworldTest : public ::testing::Test, public SharedRom {
   }
   void TearDown() override {}
 
-  zelda3::Overworld overworld_{*rom()};
+  zelda3::Overworld overworld_{rom()};
 };
 
 TEST_F(OverworldTest, OverworldLoadNoRomDataError) {
   Rom rom;
-  EXPECT_THAT(overworld_.Load(rom),
+  EXPECT_THAT(overworld_.Load(&rom),
               StatusIs(absl::StatusCode::kInvalidArgument));
 }