Remove now defunct MessageBuilder class.

mojo/mojo.gyp

Index: mojo/mojo.gyp
diff --git a/mojo/mojo.gyp b/mojo/mojo.gyp
index e323d28810962ef494114626d4fe279bd768f9d4..2cd3d5c82f1f006bab37f9b061ee40b023e1bb12 100644
--- a/mojo/mojo.gyp
+++ b/mojo/mojo.gyp
@@ -13,37 +13,6 @@
     {
       'target_name': 'mojo',
       'type': 'none',
-      'dependencies': [
-        'mojo_message',
-      ],
-    },
-    {
-      'target_name': 'mojo_message',
-      'type': 'static_library',
-      'include_dirs': [
-        '..',
-      ],
-      'sources': [
-        'public/libs/message/message.cc',
-        'public/libs/message/message.h',
-        'public/libs/message/message_builder.cc',
-        'public/libs/message/message_builder.h',
-      ],
-    },
-    {
-      'target_name': 'mojo_unittests',
-      'type': 'executable',
-      'dependencies': [
-        'mojo_message',
-        '../base/base.gyp:run_all_unittests',
-        '../testing/gtest.gyp:gtest',
-      ],
-      'include_dirs': [
-        '..'
-      ],
-      'sources': [
-        'public/libs/message/message_unittest.cc',
-      ],
     },
   ],
 }