Remove code-coverage support from chromeos test_runner

No CrOS device bot has code-coverage support enabled in its GN args.
Given this support code was added a long time ago, and because it
appears it hasn't been used since, this code is likely safe to remove.

Bug: 1288864
Change-Id: Ia0fb0d8a4af601ef5144a4997e7edac0ef7336cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3402980
Reviewed-by: Yuke Liao <liaoyuke@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/main@{#961208}

build/chromeos/test_runner.py

@@ -9,7 +9,6 @@ import collections
 import json
 import logging
 import os
-import pipes
 import re
 import shutil
 import signal
@@ -132,20 +131,6 @@ class RemoteTest:
       if args.public_image:
         self._test_cmd += ['--public-image']
 
-    # This environment variable is set for tests that have been instrumented
-    # for code coverage. Its incoming value is expected to be a location
-    # inside a subdirectory of result_dir above. This is converted to an
-    # absolute path that the vm is able to write to, and passed in the
-    # --results-src flag to cros_run_vm_test for copying out of the vm before
-    # its termination.
-    self._llvm_profile_var = None
-    if os.environ.get('LLVM_PROFILE_FILE'):
-      _, llvm_profile_file = os.path.split(os.environ['LLVM_PROFILE_FILE'])
-      self._llvm_profile_var = '/tmp/profraw/%s' % llvm_profile_file
-
-      # This should make the vm test runner exfil the profiling data.
-      self._test_cmd += ['--results-src', '/tmp/profraw']
-
     self._test_env = setup_env()
 
   @property
@@ -281,7 +266,7 @@ class TastTest(RemoteTest):
           'lacros-chrome deployment uses --nostrip by default, so it cannot '
           'be specificed with --deploy-lacros.')
 
-    if not self._llvm_profile_var and not self._logs_dir:
+    if not self._logs_dir:
       # The host-side Tast bin returns 0 when tests fail, so we need to capture
       # and parse its json results to reliably determine if tests fail.
       raise TestFormatError(
@@ -323,38 +308,6 @@ class TastTest(RemoteTest):
         os.path.relpath(self._path_to_outdir, CHROMIUM_SRC_PATH)
     ] + self._additional_args
 
-    # Coverage tests require some special pre-test setup, so use an
-    # on_device_script in that case. For all other tests, use cros_run_test's
-    # built-in '--tast' option. This gives us much better results reporting.
-    if self._llvm_profile_var:
-      # Build the shell script that will be used on the device to invoke the
-      # test.
-      device_test_script_contents = self.BASIC_SHELL_SCRIPT[:]
-      device_test_script_contents += [
-          'echo "LLVM_PROFILE_FILE=%s" >> /etc/chrome_dev.conf' %
-          (self._llvm_profile_var)
-      ]
-
-      local_test_runner_cmd = ['local_test_runner', '-waituntilready']
-      if self._use_vm:
-        # If we're running tests in VMs, tell the test runner to skip tests that
-        # aren't compatible.
-        local_test_runner_cmd.append('-extrauseflags=tast_vm')
-      if self._attr_expr:
-        local_test_runner_cmd.append(pipes.quote(self._attr_expr))
-      else:
-        local_test_runner_cmd.extend(self._tests)
-      device_test_script_contents.append(' '.join(local_test_runner_cmd))
-
-      self._on_device_script = self.write_test_script_to_disk(
-          device_test_script_contents)
-
-      self._test_cmd += [
-          '--files',
-          os.path.relpath(self._on_device_script), '--',
-          './' + os.path.relpath(self._on_device_script, self._path_to_outdir)
-      ]
-    else:
     # Capture tast's results in the logs dir as well.
     if self._logs_dir:
       self._test_cmd += [
@@ -398,11 +351,6 @@ class TastTest(RemoteTest):
       self._test_cmd.append('--nostrip')
 
   def post_run(self, return_code):
-    # If we don't need to parse the host-side Tast tool's results, fall back to
-    # the parent method's default behavior.
-    if self._llvm_profile_var:
-      return super().post_run(return_code)
-
     tast_results_path = os.path.join(self._logs_dir, 'streamed_results.jsonl')
     if not os.path.exists(tast_results_path):
       logging.error(
@@ -592,11 +540,6 @@ class GTestTest(RemoteTest):
     # Build the shell script that will be used on the device to invoke the test.
     # Stored here as a list of lines.
     device_test_script_contents = self.BASIC_SHELL_SCRIPT[:]
-    if self._llvm_profile_var:
-      device_test_script_contents += [
-          'export LLVM_PROFILE_FILE=%s' % self._llvm_profile_var,
-      ]
-
     for var_name, var_val in self._env_vars:
       device_test_script_contents += ['export %s=%s' % (var_name, var_val)]