Land chromium-side work to clean up handling of v8_target_cpu in the GN build.

chrome/test/base/js2gtest.gni

 # Copyright 2015 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.
 
 import("//build_overrides/v8.gni")
 import("//v8/snapshot_toolchain.gni")
 
 # Variables:
 #   test_type: One of 'webui', 'unit' or 'extension' indicating what
 #       environment the test runs under.
@@ skipping 19 matching lines @@
 
   gen_source_pattern = "{{source_gen_dir}}/{{source_name_part}}-gen.cc"
 
   action_foreach(action_name) {
     testonly = true
     visibility = [ ":$source_set_name" ]
     script = "//tools/gypv8sh.py"
 
     sources = invoker.sources
 
-    v8_shell_path = get_label_info("//v8:v8_shell($snapshot_toolchain)",
+    v8_shell_path = get_label_info("//v8:v8_shell($v8_snapshot_toolchain)",
                                    "root_out_dir") + "/v8_shell"
     if (is_win) {
       v8_shell_path += ".exe"
     }
 
     input_js = [
       "//chrome/third_party/mock4js/mock4js.js",
       "//chrome/test/data/webui/test_api.js",
       "//chrome/test/base/js2gtest.js",
     ]
@@ skipping 32 matching lines @@
       args += [ "--external=n" ]
     }
     args += [
       "{{source}}",
       "{{source_root_relative_dir}}/{{source_file_part}}",
       gen_source_pattern,
       rebase_path(copied_source_pattern, root_build_dir),
     ]
 
     deps = [
-      "//v8:v8_shell($snapshot_toolchain)",
+      "//v8:v8_shell($v8_snapshot_toolchain)",
     ]
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
   }
 
   if (defined(invoker.extra_js_files)) {
     copy_target_name = target_name + "_copy"
     copy(copy_target_name) {
       visibility = [ ":$source_set_name" ]
@@ skipping 24 matching lines @@
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
     if (defined(invoker.extra_js_files)) {
       data_deps = [
         ":$copy_target_name",
       ]
     }
   }
 }