Ban use of std::filesystem from nearby/sharing.

PiperOrigin-RevId: 762119139

sharing/BUILD

@@ -671,10 +671,10 @@ cc_test(
     srcs = ["nearby_sharing_settings_test.cc"],
     deps = [
         ":nearby_sharing_service",
+        "//internal/base:files",
         "//internal/platform/implementation/g3",  # fixdeps: keep
         "//internal/test",
         "//sharing/common",
-        "//sharing/common:compatible_u8_string",
         "//sharing/common:enum",
         "//sharing/internal/test:nearby_test",
         "//sharing/local_device_data:test_support",

sharing/nearby_sharing_settings_test.cc

@@ -15,7 +15,6 @@
 #include "sharing/nearby_sharing_settings.h"
 
 #include <algorithm>
-#include <filesystem>  // NOLINT(build/c++17)
 #include <memory>
 #include <string>
 #include <vector>
@@ -27,9 +26,9 @@
 #include "absl/synchronization/notification.h"
 #include "absl/time/clock.h"
 #include "absl/time/time.h"
+#include "internal/base/files.h"
 #include "internal/test/fake_device_info.h"
 #include "internal/test/fake_task_runner.h"
-#include "sharing/common/compatible_u8_string.h"
 #include "sharing/common/nearby_share_enums.h"
 #include "sharing/common/nearby_share_prefs.h"
 #include "sharing/internal/test/fake_context.h"
@@ -170,8 +169,7 @@ class NearbyShareSettingsTest : public ::testing::Test {
 
 TEST_F(NearbyShareSettingsTest, GetAndSetCustomSavePath) {
   absl::Notification notification;
-  std::string save_path =
-      GetCompatibleU8String(std::filesystem::temp_directory_path().u8string());
+  std::string save_path = GetTemporaryDirectory()->ToString();
   settings()->SetCustomSavePathAsync(save_path,
                                      [&]() { notification.Notify(); });
   Flush();