Get gpudft support working in dm, gm, nanobench and bench_pictures

Adds a new config to test distance field text.
Clean up some flags and #defines to read "distance field text",
not "distance field fonts" to be consistent with Chromium

NOTREECHECKS=true

Committed: https://skia.googlesource.com/skia/+/06ba179838ba4fe187cf290750aeeb4a02a2960b

Review URL: https://codereview.chromium.org/699453005
diff --git a/tools/flags/SkCommonFlags.cpp b/tools/flags/SkCommonFlags.cpp
index 4d329c5..c7fc17f 100644
--- a/tools/flags/SkCommonFlags.cpp
+++ b/tools/flags/SkCommonFlags.cpp
@@ -9,7 +9,7 @@
 
 DEFINE_string(config, "565 8888 pdf gpu nonrendering angle nvprmsaa4",
               "Options: 565 8888 pdf gpu nonrendering msaa4 msaa16 nvprmsaa4 nvprmsaa16 "
-              "gpunull gpudebug angle mesa");
+              "gpudft gpunull gpudebug angle mesa");
 
 DEFINE_bool(cpu, true, "master switch for running CPU-bound work.");