Have ChromeOS bin/run wrappers call test_env.py directly

Currently, when a bot runs a test (say, url_unittests) on a
is_chromeos_device build, it'll launch
`python test_env.py bin/run_url_unittests` (roughly speaking).

This CL flips that around so that the generated bin/run_ wrapper
script launches url_unittests via test_env.py (and the bot will
invoke bin/run_url_unittests directly).

This will make ChromeOS consistent with every platform other
than Android; Android will be converted to match as well in a
separate CL.

Note that apart from the test_env.py inversion, the location
of various other command line argument injections is unchanged,
so bin/run_url_unittests should run with the same args as before.

Bug: 816629
Change-Id: I5d0ac2ed847acb9685b27c41df1ed616311f64a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368537
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822012}

build/chromeos/create_test_runner_script.py

@@ -12,7 +12,7 @@ import os
 import sys
 
 SCRIPT_TEMPLATE = """\
-#!/usr/bin/env python
+#!/usr/bin/env vpython
 #
 # This file was generated by build/chromeos/create_test_runner_script.py
 
@@ -24,16 +24,16 @@ def main():
   def ResolvePath(path):
     return os.path.abspath(os.path.join(script_directory, path))
 
-  vm_test_script = os.path.abspath(
-      os.path.join(script_directory, '{vm_test_script}'))
+  test_env_py = ResolvePath('{test_env_py}')
+  vm_test_script = ResolvePath('{vm_test_script}')
 
   vm_args = {vm_test_args}
   path_args = {vm_test_path_args}
   for arg, path in path_args:
     vm_args.extend([arg, ResolvePath(path)])
 
-  os.execv(vm_test_script,
-           [vm_test_script] + vm_args + sys.argv[1:])
+  os.execv(test_env_py,
+           [test_env_py, vm_test_script] + vm_args + sys.argv[1:])
 
 if __name__ == '__main__':
   sys.exit(main())
@@ -61,6 +61,11 @@ def main(args):
   run_test_path = RelativizePathToScript(
       os.path.join(os.path.dirname(__file__), 'test_runner.py'))
 
+  test_env_path = RelativizePathToScript(
+      os.path.join(
+          os.path.dirname(os.path.dirname(os.path.dirname(__file__))),
+          'testing', 'test_env.py'))
+
   vm_test_args = []
   if args.test_exe:
     vm_test_args.extend([
@@ -110,6 +115,7 @@ def main(args):
   with open(args.script_output_path, 'w') as script:
     script.write(
         SCRIPT_TEMPLATE.format(
+            test_env_py=test_env_path,
             vm_test_script=run_test_path,
             vm_test_args=str(vm_test_args),
             vm_test_path_args=str(vm_test_path_args)))

build/config/chromeos/rules.gni

@@ -112,6 +112,7 @@ template("generate_runner_script") {
 
     data = [
       "//.vpython",
+      "//testing/test_env.py",
 
       # We use android test-runner's results libs to construct gtest output
       # json.

tools/mb/mb.py

@@ -1547,7 +1547,6 @@ class MetaBuildWrapper(object):
       ]
     elif is_cros_device and test_type != 'script':
       cmdline += [
-          '../../testing/test_env.py',
           os.path.join('bin', 'run_%s' % target),
           '--logs-dir=${ISOLATED_OUTDIR}',
       ]