565 is not this important.

tools/flags/SkCommonFlagsConfig.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCommonFlagsConfig.h"
 #include "SkImageInfo.h"
 
 #include <stdlib.h>
 
 #if SK_SUPPORT_GPU
 using sk_gpu_test::GrContextFactory;
 #endif
 
 static const char defaultConfigs[] =
-    "565 8888 gpu nonrendering"
+    "8888 gpu nonrendering"
 #if SK_ANGLE
 #ifdef SK_BUILD_FOR_WIN
     " angle"
 #endif
 #endif
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     " hwui"
 #endif
     ;
 
@@ skipping 401 matching lines @@
         if (extendedBackend.equals("gpu")) {
             parsedConfig = parse_command_line_config_gpu(tag, vias, extendedOptions);
         }
 #endif
         if (!parsedConfig) {
             parsedConfig = new SkCommandLineConfig(tag, simpleBackend, vias);
         }
         outResult->emplace_back(parsedConfig);
     }
 }