Add config options to run different GPU APIs to dm and nanobench

tools/flags/SkCommonFlags.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCommonFlags.h"
 
-DEFINE_string(config, "565 8888 gpu nonrendering angle hwui ", "Options: "
-              "565 8888 angle debug gpu gpudebug gpudft gpunull hwui mesa "
-              "msaa16 msaa4 nonrendering null nullgpu nvprmsaa16 nvprmsaa4 "
-              "pdf skp svg xps (and maybe more)");
-
 DEFINE_bool(cpu, true, "master switch for running CPU-bound work.");
 
 DEFINE_bool(dryRun, false,
             "just print the tests that would be run, without actually running them.");
 
 DEFINE_bool(gpu, true, "master switch for running GPU-bound work.");
 
-DEFINE_string(gpuAPI, "", "Force use of specific gpu API.  Using \"gl\" "
-              "forces OpenGL API. Using \"gles\" forces OpenGL ES API. "
-              "Defaults to empty string, which selects the API native to the "
-              "system.");
-
 DEFINE_string(images, "", "Directory of images to decode.");
 
 DEFINE_string2(match, m, nullptr,
                "[~][^]substring[$] [...] of GM name to run.\n"
                "Multiple matches may be separated by spaces.\n"
                "~ causes a matching GM to always be skipped\n"
                "^ requires the start of the GM to match\n"
                "$ requires the end of the GM to match\n"
                "^ and $ requires an exact match\n"
                "If a GM does not match any list entry,\n"
@@ skipping 14 matching lines @@
 
 DEFINE_bool2(veryVerbose, V, false, "tell individual tests to be verbose.");
 
 DEFINE_string2(writePath, w, "", "If set, write bitmaps here as .pngs.");
 
 DEFINE_string(key, "",
               "Space-separated key/value pairs to add to JSON identifying this builder.");
 DEFINE_string(properties, "",
               "Space-separated key/value pairs to add to JSON identifying this run.");