refactor(srp): add renderer backend registry seam

tests/Rendering/unit/test_camera_scene_renderer.cpp

@@ -50,6 +50,38 @@ CameraFrameStageSourceBinding ResolveStageSourceBinding(
     return ResolveCameraFrameStageSourceBinding(stage, plan);
 }
 
+std::shared_ptr<const RenderPipelineAsset>
+CreateBuiltinForwardPipelineRendererAssetForTest() {
+    return std::make_shared<Pipelines::BuiltinForwardPipelineAsset>();
+}
+
+class ScopedPipelineRendererAssetFactoryRegistration final {
+public:
+    ScopedPipelineRendererAssetFactoryRegistration(
+        std::string key,
+        Internal::PipelineRendererAssetFactory factory)
+        : m_key(std::move(key))
+        , m_registered(
+              Internal::RegisterPipelineRendererAssetFactory(
+                  m_key,
+                  std::move(factory))) {
+    }
+
+    ~ScopedPipelineRendererAssetFactoryRegistration() {
+        if (m_registered) {
+            (void)Internal::UnregisterPipelineRendererAssetFactory(m_key);
+        }
+    }
+
+    bool IsRegistered() const {
+        return m_registered;
+    }
+
+private:
+    std::string m_key;
+    bool m_registered = false;
+};
+
 struct MockPipelineState {
     int initializeCalls = 0;
     int shutdownCalls = 0;
@@ -4543,6 +4575,31 @@ TEST(
     Pipelines::ClearManagedRenderPipelineBridge();
 }
 
+TEST(
+    RenderPipelineFactory_Test,
+    RegisteredAliasKeyResolvesPipelineRendererAssetAndNativeSceneRenderer) {
+    ScopedPipelineRendererAssetFactoryRegistration registration(
+        "BuiltinForwardAlias",
+        &CreateBuiltinForwardPipelineRendererAssetForTest);
+    ASSERT_TRUE(registration.IsRegistered());
+
+    std::shared_ptr<const RenderPipelineAsset> rendererAsset =
+        Internal::CreatePipelineRendererAssetByKey("BuiltinForwardAlias");
+    ASSERT_NE(rendererAsset, nullptr);
+
+    std::shared_ptr<const RenderPipelineAsset> resolvedAsset = nullptr;
+    std::unique_ptr<NativeSceneRenderer> sceneRenderer =
+        Internal::CreateNativeSceneRendererFromAsset(
+            rendererAsset,
+            &resolvedAsset);
+
+    ASSERT_NE(sceneRenderer, nullptr);
+    EXPECT_EQ(resolvedAsset, rendererAsset);
+    EXPECT_NE(
+        dynamic_cast<Pipelines::BuiltinForwardPipeline*>(sceneRenderer.get()),
+        nullptr);
+}
+
 TEST(
     ScriptableRenderPipelineHost_Test,
     FallsBackToRendererWhenStageRecorderDeclinesRecording) {