Revert of Sync more GN unit tests with GYP.

components/sessions/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 config("implementation") {
   defines = [ "SESSIONS_IMPLEMENTATION" ]
@@ skipping 106 matching lines @@
       "base_session_service_test_helper.cc",
       "base_session_service_test_helper.h",
     ]
   }
 }
 
 if (!is_ios && !is_android) {
   source_set("unit_tests") {
     testonly = true
     sources = [
-      "content/content_serialized_navigation_builder_unittest.cc",
-      "content/content_serialized_navigation_driver_unittest.cc",
-      "ios/ios_serialized_navigation_builder_unittest.cc",
-      "ios/ios_serialized_navigation_driver_unittest.cc",
-      "serialized_navigation_entry_unittest.cc",
       "session_backend_unittest.cc",
       "session_types_unittest.cc",
     ]
     deps = [
       ":sessions",
-      ":test_support",
       "//base/test:test_support",
       "//testing/gtest",
       "//third_party/protobuf:protobuf_lite",
     ]
   }
 }