[libfuzzer] Add expat_xml_parse_fuzzer for third_party/expat.

third_party/expat/BUILD.gn

 # Copyright (c) 2013 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("//build/config/chromecast_build.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 
 # Chromecast doesn't ship expat as a system library
 if (is_linux && !is_chromecast) {
   config("expat_config") {
     libs = [ "expat" ]
   }
 
   group("expat") {
     public_configs = [ ":expat_config" ]
   }
@@ skipping 14 matching lines @@
     public_configs = [ ":expat_config" ]
 
     defines = [ "_LIB" ]
     if (is_win) {
       defines += [ "COMPILED_FROM_DSP" ]
     } else {
       defines += [ "HAVE_EXPAT_CONFIG_H" ]
     }
   }
 }
+
+fuzzer_test("expat_xml_parse_fuzzer") {
+  sources = [
+    "fuzz/expat_xml_parse_fuzzer.cc",
+  ]
+  deps = [
+    ":expat",
+  ]
+  dict = "//testing/libfuzzer/fuzzers/dicts/xml.dict"
+}