[ios] remove the xctest arg with enable_unittests_xctest

enable_run_ios_unittests_with_xctest ensures that the test target
type is ios_xctest_test. However, ie/ ios-beta-device, the unit
tests are actually not run with --xctest flag on.

To allow flexibility, we'll pass the --xctest flag in testing/
buildbot/ if needed, instead of mandating this, and to comply
with downstream behaviour.

Bug: 912681
Change-Id: I36769420792e7959a3e8873551b6968c770d1c97
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368492
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/master@{#800643}

testing/buildbot/mixins.pyl

@@ -978,4 +978,11 @@
       ],
     },
   },
+  'xctest': {
+    '$mixin_append': {
+      'args': [
+        '--xctest',
+      ],
+    },
+  },
 }

testing/buildbot/test_suites.pyl

@@ -5536,6 +5536,9 @@
     # ios13-beta-sim already runs 13.x and 12.4
     'ios14_beta_simulator_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_X_14_0',
         ],
@@ -5559,6 +5562,9 @@
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_6S_PLUS_14_0',
           'SIM_IPHONE_X_14_0',
@@ -5569,6 +5575,9 @@
 
     'ios14_sdk_simulator_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           # 14.0 Sims
           'SIM_IPHONE_6S_14_0',
@@ -5593,6 +5602,9 @@
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           # 14.0 Sims
           'SIM_IPHONE_6S_PLUS_14_0',
@@ -5603,12 +5615,18 @@
 
     'ios_asan_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_X_13_6',
           'SIM_IPAD_AIR_2_13_6',
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_X_13_6',
           'SIM_IPAD_AIR_2_13_6',
@@ -5634,6 +5652,9 @@
 
     'ios_code_coverage_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_6S_12_4',
           'SIM_IPHONE_6S_13_6',
@@ -5660,6 +5681,9 @@
         ],
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_6S_PLUS_13_6',
           'SIM_IPHONE_6S_13_6',
@@ -5701,6 +5725,9 @@
 
     'ios_simulator_multi_window_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPAD_AIR_2_13_6',
         ]
@@ -5718,6 +5745,9 @@
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPAD_AIR_2_13_6',
         ]
@@ -5726,6 +5756,9 @@
 
     'ios_simulator_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_6S_12_4',
           'SIM_IPHONE_6S_13_6',
@@ -5739,6 +5772,9 @@
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_6S_PLUS_13_6',
           'SIM_IPHONE_6S_13_6',
@@ -5750,6 +5786,9 @@
 
     'ios_webkit_tot_tests': {
       'ios_common_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_X_13_5',
           'SIM_IPAD_AIR_2_13_5',
@@ -5770,6 +5809,9 @@
         ]
       },
       'ios_screen_size_dependent_tests': {
+        'mixins': [
+          'xctest',
+        ],
         'variants': [
           'SIM_IPHONE_X_13_5',
           'SIM_IPAD_AIR_2_13_5',

testing/test.gni

@@ -273,10 +273,6 @@ template("test") {
         "@WrappedPath(${_root_build_dir}/${_test_target}.app)",
       ]
 
-      if (enable_run_ios_unittests_with_xctest) {
-        executable_args += [ "--xctest" ]
-      }
-
       wrapper_output_name = "${_wrapper_output_name}"
     }