Replace inappropriate uses of DIR_ASSETS

Convert test code accessing test data to DIR_GEN_TEST_DATA_ROOT or
DIR_SRC_TEST_DATA_ROOT as appropriate.

Convert one Fuchsia-specific use to the literal it intends to use.

Also document some uses of DIR_GEN_TEST_DATA_ROOT added in
crrev.com/c/3237884.

Bug: 1262430
Change-Id: I3e32495ef4d49f98b3e58971cd30990be427e698
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3254176
Auto-Submit: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Fabrice de Gans <fdegans@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Commit-Queue: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#938352}
NOKEYCHECK=True
GitOrigin-RevId: 95fefdd6c41d7d3736dd861332f2f4feb6e4dc7e
diff --git a/policy/fuchsia/sandbox_policy_fuchsia.cc b/policy/fuchsia/sandbox_policy_fuchsia.cc
index 2900ad8..fb97579 100644
--- a/policy/fuchsia/sandbox_policy_fuchsia.cc
+++ b/policy/fuchsia/sandbox_policy_fuchsia.cc
@@ -31,6 +31,7 @@
 #include "base/containers/span.h"
 #include "base/files/file_util.h"
 #include "base/fuchsia/default_job.h"
+#include "base/fuchsia/file_utils.h"
 #include "base/fuchsia/filtered_service_directory.h"
 #include "base/fuchsia/fuchsia_logging.h"
 #include "base/fuchsia/process_context.h"
@@ -205,9 +206,8 @@
 
   // Map /pkg (read-only files deployed from the package) into the child's
   // namespace.
-  base::FilePath package_root;
-  base::PathService::Get(base::DIR_ASSETS, &package_root);
-  options->paths_to_clone.push_back(package_root);
+  options->paths_to_clone.push_back(
+      base::FilePath(base::kPackageRootDirectoryPath));
 
   // If /config/data/tzdata/icu/ exists then it contains up-to-date timezone
   // data which should be provided to all sub-processes, for consistency.