[bazel_migration][fake-object] //sdk/lib/driver/fake-object/cpp

- Convert `cpp` (`idk_cc_source_library()`), `fake_object_test`
  (`fx_cc_test()`), and `fake_object_test_package`
  (`fx_unittest_package()`) to `BUILD.bazel`.
- Register `//sdk/lib/driver/fake-object/cpp:cpp_idk` in
  `STABLE_CC_SOURCE_LIBRARY_ATOMS` in `sdk/atom_lists.bzl`.
- Sync targets back to `BUILD.gn` via `bazel2gn` and keep
  `group("tests")` in `BUILD.gn`.

Bug: 571374004
Bazel-Migration-Target: //sdk/lib/driver/fake-object/cpp:cpp
Bazel-Migration-Target: //sdk/lib/driver/fake-object/cpp:fake_object_test
Bazel-Migration-Target: //sdk/lib/driver/fake-object/cpp:fake_object_test_package
Test: fx bazel build --config=fuchsia_platform @//sdk/lib/driver/fake-object/cpp:cpp @//sdk/lib/driver/fake-object/cpp:fake_object_test_package
Run-All-Tests: true
TAG: planter planter-20261030-2d69c1d68e8-local
Change-Id: I4dd04d10d768df7247b436e588bcc8ad8f2bd212
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1936270
Agent-Code-Review: Fuchsia CL Risk (Advisory) <groupagent-fuchsia-risk@google.com>
Commit-Queue: Angelica Rosenzweig Castillo <rosenzwa@google.com>
Fuchsia-Auto-Submit: Angelica Rosenzweig Castillo <rosenzwa@google.com>
Presubmit-Verified: fuchsia-internal-scoped@luci-project-accounts.iam.gserviceaccount.com <fuchsia-internal-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Kevin Lindkvist <lindkvist@google.com>
Risk: Fuchsia CL Risk (Advisory) <groupagent-fuchsia-risk@google.com>
Reviewed-by: Jay Zhuang <jayzhuang@google.com>
diff --git a/sdk/atom_lists.bzl b/sdk/atom_lists.bzl
index 4cd4672..3d75f92 100644
--- a/sdk/atom_lists.bzl
+++ b/sdk/atom_lists.bzl
@@ -19,6 +19,7 @@
     "//sdk/lib/component/incoming/cpp:cpp_idk",
     "//sdk/lib/component/outgoing/cpp:cpp_idk",
     "//sdk/lib/driver/devfs/cpp:cpp_idk",
+    "//sdk/lib/driver/fake-object/cpp:cpp_idk",
     "//sdk/lib/driver/runtime:driver_runtime_cpp_idk",
     "//sdk/lib/driver/runtime:driver_runtime_env_cpp_idk",
     "//sdk/lib/driver/runtime:driver_runtime_env_idk",
diff --git a/sdk/lib/BUILD.bazel b/sdk/lib/BUILD.bazel
index 07c665e51..483fbb7 100644
--- a/sdk/lib/BUILD.bazel
+++ b/sdk/lib/BUILD.bazel
@@ -10,6 +10,7 @@
     tests = [
         "//sdk/lib/async/rust/scope_dispatcher:libasync_scope_dispatcher_tests",
         "//sdk/lib/driver/debug/rust:driver_debug_tests",
+        "//sdk/lib/driver/fake-object/cpp:fake_object_test_package",
         "//sdk/lib/driver/mmio/rust:unittests",
         "//sdk/lib/driver/mock-mmio/rust:unittests",
         "//sdk/lib/fdio/tests/getaddrinfo:getaddrinfo_tests",
diff --git a/sdk/lib/driver/fake-object/cpp/BUILD.bazel b/sdk/lib/driver/fake-object/cpp/BUILD.bazel
new file mode 100644
index 0000000..a65f1ed
--- /dev/null
+++ b/sdk/lib/driver/fake-object/cpp/BUILD.bazel
@@ -0,0 +1,52 @@
+# Copyright 2026 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+load("//build/bazel/rules/cc:fx_cc_test.bzl", "fx_cc_test")
+load("//build/bazel/rules/idk:idk_cc_source_library.bzl", "idk_cc_source_library")
+load("//build/bazel/rules/testing:fx_unittest_package.bzl", "fx_unittest_package")
+
+package(default_applicable_licenses = ["//:license"])
+
+idk_cc_source_library(
+    name = "cpp",
+    srcs = [
+        "fake-handle.cc",
+        "fake-object.cc",
+        "internal.h",
+    ],
+    hdrs = ["fake-object.h"],
+    api_area = "Driver SDK",
+    category = "partner",
+    idk_name = "driver_fake_object_cpp",
+    include_base = "//sdk",
+    public_configs = ["//sdk/config"],
+    stable = True,
+    visibility = [
+        "//build/sdk:__pkg__",
+        "//sdk/lib/driver/fake-bti/cpp:__pkg__",
+        "//sdk/lib/driver/fake-resource/cpp:__pkg__",
+    ],
+    deps = [
+        "//sdk/lib/fdio",
+        "//zircon/system/ulib/zx",
+    ],
+)
+
+fx_cc_test(
+    name = "fake_object_test",
+    srcs = [
+        "fake-object-test.cc",
+        "internal.h",
+    ],
+    deps = [
+        ":cpp",
+        "//zircon/system/ulib/zxtest",
+    ],
+)
+
+fx_unittest_package(
+    name = "fake_object_test_package",
+    unit_tests = [":fake_object_test"],
+    visibility = ["//sdk/lib:__pkg__"],
+)
diff --git a/sdk/lib/driver/fake-object/cpp/BUILD.gn b/sdk/lib/driver/fake-object/cpp/BUILD.gn
index c7e6ed5..fba1852 100644
--- a/sdk/lib/driver/fake-object/cpp/BUILD.gn
+++ b/sdk/lib/driver/fake-object/cpp/BUILD.gn
@@ -2,45 +2,66 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/components.gni")
-import("//build/cpp/sdk_source_set.gni")
-import("//build/test.gni")
-
 group("tests") {
   testonly = true
   deps = [ ":fake_object_test_package" ]
 }
 
-sdk_source_set("cpp") {
-  category = "partner"
-  stable = true
-  sdk_name = "driver_fake_object_cpp"
-  include_base = "//sdk"
+## BAZEL2GN SENTINEL - DO NOT EDIT BELOW THIS LINE ##
+#
+#  ________  _________  ________  ________
+# |\   ____\|\___   ___\\   __  \|\   __  \
+# \ \  \___|\|___ \  \_\ \  \|\  \ \  \|\  \
+#  \ \_____  \   \ \  \ \ \  \\\  \ \   ____\
+#   \|____|\  \   \ \  \ \ \  \\\  \ \  \___|
+#     ____\_\  \   \ \__\ \ \_______\ \__\
+#    |\_________\   \|__|  \|_______|\|__|
+#    \|_________|
+#
+#
+# AUTO-GENERATED - DO NOT EDIT
+#
+# The targets below are auto-generated based on the targets defined in the
+# BUILD.bazel file from the same directory. If you made changes to targets in
+# Bazel, instead of editing this file manually, run:
+#
+#   > fx bazel2gn
+#
+# Please do NOT edit this file directly. Instead, edit the BUILD.bazel file and
+# rerun bazel2gn.
 
+import("//build/tools/bazel2gn/bazel_migration.gni")
+
+sdk_source_set("cpp") {
   sources = [
     "fake-handle.cc",
     "fake-object.cc",
     "internal.h",
   ]
-
   public = [ "fake-object.h" ]
-
+  sdk_area = "Driver SDK"
+  category = "partner"
+  sdk_name = "driver_fake_object_cpp"
+  include_base = "//sdk"
+  public_configs = [ "//sdk/config" ]
+  stable = true
+  visibility = [
+    ":*",
+    "//build/sdk:*",
+    "//sdk/lib/driver/fake-bti/cpp:*",
+    "//sdk/lib/driver/fake-resource/cpp:*",
+  ]
   public_deps = [
     "//sdk/lib/fdio",
     "//zircon/system/ulib/zx",
   ]
-
-  public_configs = [ "//sdk/config" ]
 }
 
 test("fake_object_test") {
-  testonly = true
-  output_name = "fake_object_test"
   sources = [
     "fake-object-test.cc",
     "internal.h",
   ]
-
   deps = [
     ":cpp",
     "//zircon/system/ulib/zxtest",
@@ -48,5 +69,11 @@
 }
 
 fuchsia_unittest_package("fake_object_test_package") {
+  package_name = "fake_object_test_package-gn"
+  component_name = "fake_object_test_package"
   deps = [ ":fake_object_test" ]
+  visibility = [
+    ":*",
+    "//sdk/lib:*",
+  ]
 }