[unification] Move //zircon/system/utest/task-utils to the GN build

Generated with: //scripts/unification/move_zn_element.py

scripts/unification/verify_element_move.py --reference local/initial.json:

<none>

Bug: 36139
Change-Id: Ia9e7f70f17cddca273cc6f9aff8a54e06506528e
diff --git a/build/unification/images/BUILD.gn b/build/unification/images/BUILD.gn
index bf7a76e..0f52a23 100644
--- a/build/unification/images/BUILD.gn
+++ b/build/unification/images/BUILD.gn
@@ -703,7 +703,6 @@
     ":test.sys.sysmem-unittest",
     ":test.sys.tas5782-test",
     ":test.sys.tas5805-test",
-    ":test.sys.task-utils-test",
     ":test.sys.test-exceptions-test",
     ":test.sys.tftp-test",
     ":test.sys.thermal-cli-test",
@@ -1166,7 +1165,6 @@
     ":test.sys.sysmem-unittest",
     ":test.sys.tas5782-test",
     ":test.sys.tas5805-test",
-    ":test.sys.task-utils-test",
     ":test.sys.test-exceptions-test",
     ":test.sys.tftp-test",
     ":test.sys.thermal-cli-test",
@@ -2221,7 +2219,7 @@
     #":test.sys.sysmem-unittest",
     #":test.sys.tas5782-test",
     #":test.sys.tas5805-test",
-    #":test.sys.task-utils-test",
+    "//zircon/system/utest/task-utils:task-utils-manifest",
     #":test.sys.test-exceptions-test",
     "//zircon/system/ulib/test-utils/test:test-utils-manifest",
     #":test.sys.tftp-test",
@@ -2671,7 +2669,7 @@
     #":test.sys.sysmem-unittest",
     #":test.sys.tas5782-test",
     #":test.sys.tas5805-test",
-    #":test.sys.task-utils-test",
+    "//zircon/system/utest/task-utils:task-utils-manifest",
     #":test.sys.test-exceptions-test",
     "//zircon/system/ulib/test-utils/test:test-utils-manifest",
     #":test.sys.tftp-test",
diff --git a/zircon/system/utest/BUILD.gn b/zircon/system/utest/BUILD.gn
index 6a869f7..e43a760 100644
--- a/zircon/system/utest/BUILD.gn
+++ b/zircon/system/utest/BUILD.gn
@@ -243,7 +243,6 @@
       "svchost",
       "sysinfo",
       "sysmem",
-      "task-utils",
       "thread-initial-state",
       "thread-safe-deleter",
       "timers",
diff --git a/zircon/system/utest/task-utils/BUILD.gn b/zircon/system/utest/task-utils/BUILD.gn
index 551bbaed..0d25330 100644
--- a/zircon/system/utest/task-utils/BUILD.gn
+++ b/zircon/system/utest/task-utils/BUILD.gn
@@ -2,13 +2,33 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-zx_test("task-utils") {
+##########################################
+# Though under //zircon, this build file #
+# is meant to be used in the Fuchsia GN  #
+# build.                                 #
+# See fxb/36139.                         #
+##########################################
+
+assert(!defined(zx) || zx != "/",
+       "This file can only be used in the Fuchsia GN build.")
+
+import("//build/test.gni")
+import("//build/unification/images/migrated_manifest.gni")
+
+test("task-utils") {
+  # Dependent manifests unfortunately cannot be marked as `testonly`.
+  # Remove when converting this file to proper GN build idioms.
+  testonly = false
+  configs += [ "//build/unification/config:zircon-migrated" ]
   sources = [ "walker.cc" ]
   deps = [
-    "$zx/system/fidl/fuchsia-sysinfo:c",
-    "$zx/system/ulib/fdio",
-    "$zx/system/ulib/task-utils",
-    "$zx/system/ulib/unittest",
-    "$zx/system/ulib/zircon",
+    "//zircon/public/lib/fdio",
+    "//zircon/public/lib/task-utils",
+    "//zircon/public/lib/unittest",
+    "//zircon/system/fidl/fuchsia-sysinfo:c",
   ]
 }
+
+migrated_manifest("task-utils-manifest") {
+  deps = [ ":task-utils" ]
+}