Add ICU integration for fuzzer test

Initialize ICU to ICU data file during fuzzing. This is a fix for CHECK
failure caused during clusterfuzz testing.

Bug: 808412
Change-Id: Ied129095f1650a97a7767b7dde8ea2084b9ceb2f
Reviewed-on: https://chromium-review.googlesource.com/902583Reviewed-by: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Kim Paulhamus <kpaulhamus@chromium.org>
Commit-Queue: Jun Choi <hongjunchoi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535909}

device/fido/BUILD.gn

@@ -205,6 +205,8 @@ fuzzer_test("ctap_response_fuzzer") {
   ]
   deps = [
     ":fido",
+    "//base",
+    "//base:i18n",
   ]
   seed_corpus = "ctap_response_fuzzer_corpus/"
   libfuzzer_options = [ "max_len=65537" ]

device/fido/ctap_response_fuzzer.cc

@@ -8,12 +8,28 @@
 #include <algorithm>
 #include <vector>
 
+#include "base/at_exit.h"
+#include "base/i18n/icu_util.h"
 #include "device/fido/authenticator_get_assertion_response.h"
 #include "device/fido/authenticator_get_info_response.h"
 #include "device/fido/authenticator_make_credential_response.h"
 #include "device/fido/ctap_constants.h"
 #include "device/fido/device_response_converter.h"
 
+namespace device {
+
+// Creating a PublicKeyCredentialUserEntity from a CBOR value can involve URL
+// parsing, which relies on ICU for IDN handling. This is why ICU needs to be
+// initialized explicitly.
+// See: http://crbug/808412
+struct IcuEnvironment {
+  IcuEnvironment() { CHECK(base::i18n::InitializeICU()); }
+  // Used by ICU integration.
+  base::AtExitManager at_exit_manager;
+};
+
+IcuEnvironment* env = new IcuEnvironment();
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   std::vector<uint8_t> input(data, data + size);
   device::ReadCTAPMakeCredentialResponse(
@@ -25,3 +41,5 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 
   return 0;
 }
+
+}  // namespace device