Set enable_app_list=1 now only on ChromeOS.

testing/buildbot/chromium.mac.json

Index: testing/buildbot/chromium.mac.json
diff --git a/testing/buildbot/chromium.mac.json b/testing/buildbot/chromium.mac.json
index 13c8b44ad824b63dd3138b640f902ccbe9c339da..debdf08ae7fe6b125cf4d1d02cb63c6d74a5edb8 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -14,12 +14,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
@@ -292,12 +286,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
@@ -567,12 +555,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
@@ -898,12 +880,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
@@ -1229,12 +1205,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {
@@ -1560,12 +1530,6 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "app_list_unittests"
-      },
-      {
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        },
         "test": "base_unittests"
       },
       {