Run app_shell_browsertests and app_shell_unittests on mac trybots and waterfall bots.

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 c74cd86ca1a5849e9d064521060f37985908a756..f20d06aecc9fbbd0bba91d6312447cbc80427498 100644
--- a/testing/buildbot/chromium.mac.json
+++ b/testing/buildbot/chromium.mac.json
@@ -13,6 +13,8 @@
           "can_use_on_swarming_builders": true
         }
       },
+      "app_shell_browsertests",
+      "app_shell_unittests",
       {
         "test": "base_unittests",
         "swarming": {
@@ -136,6 +138,8 @@
           "can_use_on_swarming_builders": true
         }
       },
+      "app_shell_browsertests",
+      "app_shell_unittests",
       {
         "test": "base_unittests",
         "swarming": {
@@ -259,6 +263,8 @@
           "can_use_on_swarming_builders": true
         }
       },
+      "app_shell_browsertests",
+      "app_shell_unittests",
       {
         "test": "base_unittests",
         "swarming": {
@@ -382,6 +388,8 @@
           "can_use_on_swarming_builders": true
         }
       },
+      "app_shell_browsertests",
+      "app_shell_unittests",
       {
         "test": "base_unittests",
         "swarming": {