Add a version of gpu_fuzzer that is backed by the NULL ANGLE backend

gpu/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//build/config/ui.gni")
 
 config("gpu_implementation") {
   defines = [ "GPU_IMPLEMENTATION" ]
@@ skipping 381 matching lines @@
   deps = [
     ":gpu",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//gpu/command_buffer/common:gles2_utils",
     "//ui/gfx/geometry",
     "//ui/gl",
     "//ui/gl:test_support",
   ]
 
-  libfuzzer_options = [
-    "max_len=16384",
-    "use_traces=1",
+  libfuzzer_options = [ "max_len=16384" ]
+}
+
+fuzzer_test("gpu_fuzzer_angle") {
+  sources = [
+    "command_buffer/tests/fuzzer_main.cc",
   ]
+
+  defines = [ "GPU_FUZZER_USE_ANGLE" ]
+
+  deps = [
+    ":gpu",
+    "//base",
+    "//base/third_party/dynamic_annotations",
+    "//gpu/command_buffer/common:gles2_utils",
+    "//ui/gfx/geometry",
+    "//ui/gl",
+    "//ui/gl:test_support",
+  ]
+
+  libfuzzer_options = [ "max_len=16384" ]
 }