[iOS fuzzer] Fixed crashes in chrome_app_startup_parameters fuzzer

Fixed two issues with crashing in the three fuzzers for
chrome_app_startup_parameters. An AtExitManager was added into the
fuzzer's environment, which is needed as a callback for CHECKs that
naturally fail in the fuzzer's limited environment. Also, we
instantiate the i18n library since it is needed by GURL inside the
fuzzed function with i18n::InitializeICU().

Bug: 1523661
Change-Id: I8a4e6bf2b3410c65b119fad006c3ac24fb34145e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5253738
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Nicolas MacBeth <nicolasmacbeth@google.com>
Cr-Commit-Position: refs/heads/main@{#1255612}

diff --git a/ios/chrome/app/startup/BUILD.gn b/ios/chrome/app/startup/BUILD.gn
index 4bc4927..b07dc39 100644
--- a/ios/chrome/app/startup/BUILD.gn
+++ b/ios/chrome/app/startup/BUILD.gn

@@ -131,6 +131,7 @@
   public_deps = [
     ":startup",
     "//base",
+    "//base:i18n",
     "//base/test:test_support",
     "//ios/chrome/app:tests_fake_hook",
     "//ios/chrome/browser/providers:chromium_providers",

diff --git a/ios/chrome/app/startup/chrome_app_startup_parameters_external_actions_fuzzer.mm b/ios/chrome/app/startup/chrome_app_startup_parameters_external_actions_fuzzer.mm
index baa8354..ce0788c 100644
--- a/ios/chrome/app/startup/chrome_app_startup_parameters_external_actions_fuzzer.mm
+++ b/ios/chrome/app/startup/chrome_app_startup_parameters_external_actions_fuzzer.mm

@@ -4,7 +4,17 @@
 
 #import "ios/chrome/app/startup/chrome_app_startup_parameters.h"
 
+#import "base/at_exit.h"
+#import "base/i18n/icu_util.h"
+
+struct Environment {
+  Environment() { CHECK(base::i18n::InitializeICU()); }
+  base::AtExitManager at_exit;
+};
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  static Environment env;
+
   std::string str = std::string(reinterpret_cast<const char*>(data), size);
 
   NSString* formatted_string = [NSString

diff --git a/ios/chrome/app/startup/chrome_app_startup_parameters_googlechromes_fuzzer.mm b/ios/chrome/app/startup/chrome_app_startup_parameters_googlechromes_fuzzer.mm
index 69e90a26..f41b14c 100644
--- a/ios/chrome/app/startup/chrome_app_startup_parameters_googlechromes_fuzzer.mm
+++ b/ios/chrome/app/startup/chrome_app_startup_parameters_googlechromes_fuzzer.mm

@@ -4,7 +4,17 @@
 
 #import "ios/chrome/app/startup/chrome_app_startup_parameters.h"
 
+#import "base/at_exit.h"
+#import "base/i18n/icu_util.h"
+
+struct Environment {
+  Environment() { CHECK(base::i18n::InitializeICU()); }
+  base::AtExitManager at_exit;
+};
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  static Environment env;
+
   std::string str = std::string(reinterpret_cast<const char*>(data), size);
 
   NSString* formatted_string =

diff --git a/ios/chrome/app/startup/chrome_app_startup_parameters_scheme_fuzzer.mm b/ios/chrome/app/startup/chrome_app_startup_parameters_scheme_fuzzer.mm
index 8b20108..0396b77 100644
--- a/ios/chrome/app/startup/chrome_app_startup_parameters_scheme_fuzzer.mm
+++ b/ios/chrome/app/startup/chrome_app_startup_parameters_scheme_fuzzer.mm

@@ -4,7 +4,17 @@
 
 #import "ios/chrome/app/startup/chrome_app_startup_parameters.h"
 
+#import "base/at_exit.h"
+#import "base/i18n/icu_util.h"
+
+struct Environment {
+  Environment() { CHECK(base::i18n::InitializeICU()); }
+  base::AtExitManager at_exit;
+};
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  static Environment env;
+
   std::string str = std::string(reinterpret_cast<const char*>(data), size);
 
   NSString* formatted_string = [NSString stringWithFormat:@"%s", str.c_str()];