Convert mus apptests to shelltests

testing/buildbot/chromium.linux.json

Index: testing/buildbot/chromium.linux.json
diff --git a/testing/buildbot/chromium.linux.json b/testing/buildbot/chromium.linux.json
index 80a577ff4071e21a6bc968b994cecd5aa2a28242..982f1dcec230e7ec959e410330b079f6a3d633ac 100644
--- a/testing/buildbot/chromium.linux.json
+++ b/testing/buildbot/chromium.linux.json
@@ -842,6 +842,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "mus_ws_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {
@@ -932,9 +938,6 @@
         "test": "views_unittests"
       },
       {
-        "test": "window_manager_unittests"
-      },
-      {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
@@ -1241,6 +1244,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "mus_ws_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {