Deploy a single MacBook Pro Retina with AMD GPU on GPU FYI waterfall.

masters/master.chromium.gpu.fyi/slaves.cfg

Index: masters/master.chromium.gpu.fyi/slaves.cfg
diff --git a/masters/master.chromium.gpu.fyi/slaves.cfg b/masters/master.chromium.gpu.fyi/slaves.cfg
index 8826be52b1ec48f2952e0e491be94fccb4fd4fa7..97f36c8f2b0b41b0a266dd85a862d359412d02fc 100644
--- a/masters/master.chromium.gpu.fyi/slaves.cfg
+++ b/masters/master.chromium.gpu.fyi/slaves.cfg
@@ -369,6 +369,20 @@ slaves = [
   },
   {
     'master': 'ChromiumGPUFYI',
+    'hostname': 'build52-b1',
+    'builder': 'Mac Retina Release (AMD)',
+    'os': 'mac',
+    'version': '10.11',
+    'bits': '64',
+    'recipe': 'chromium',
+    'build_config': 'Release',
+    # This bot uses recipe-side triggers.
+    'triggered_by': 'none',
+    # Nearly all bots on these waterfalls are auto-rebooted between
+    # runs for stability.
+  },
+  {
+    'master': 'ChromiumGPUFYI',
     'hostname': 'slave60-c1',
     'builder': 'GPU Linux Builder',
     'os': 'linux',