gn: fix fiddle

BUILD.gn

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 declare_args() {
 }
 
 skia_public_includes = [
   "include/android",
@@ skipping 290 matching lines @@
     libs += [ "OSMesa" ]
   }
 
   sources = [
     "tools/fiddle/draw.cpp",
     "tools/fiddle/fiddle_main.cpp",
   ]
   deps = [
     ":skia",
     ":skia.h",
+    ":tool_utils",
   ]
+  testonly = true
 }
 
 template("test_lib") {
   config(target_name + "_config") {
     include_dirs = invoker.public_include_dirs
   }
   source_set(target_name) {
     forward_variables_from(invoker, "*", [ "public_include_dirs" ])
     public_configs = [
       ":" + target_name + "_config",
@@ skipping 158 matching lines @@
       ":flags",
       ":gm",
       ":gpu_tool_utils",
       ":skia",
       ":tool_utils",
       "//third_party/jsoncpp",
     ]
     testonly = true
   }
 }