fix: record helper error messages in electron_main_mac (#37811)

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Jeremy Rose <[email protected]>

shell/app/electron_main_mac.cc

@@ -18,6 +18,14 @@
 #include "sandbox/mac/seatbelt_exec.h"  // nogncheck
 #endif
 
+extern "C" {
+// abort_report_np() records the message in a special section that both the
+// system CrashReporter and Crashpad collect in crash reports. Using a Crashpad
+// Annotation would be preferable, but this executable cannot depend on
+// Crashpad directly.
+void abort_report_np(const char* fmt, ...);
+}
+
 namespace {
 
 [[maybe_unused]] bool IsEnvSet(const char* name) {
@@ -25,6 +33,20 @@ namespace {
   return indicator && indicator[0] != '\0';
 }
 
+#if defined(HELPER_EXECUTABLE) && !defined(MAS_BUILD)
+[[noreturn]] void FatalError(const char* format, ...) {
+  va_list valist;
+  va_start(valist, format);
+  char message[4096];
+  if (vsnprintf(message, sizeof(message), format, valist) >= 0) {
+    fputs(message, stderr);
+    abort_report_np("%s", message);
+  }
+  va_end(valist);
+  abort();
+}
+#endif
+
 }  // namespace
 
 int main(int argc, char* argv[]) {
@@ -42,27 +64,23 @@ int main(int argc, char* argv[]) {
   uint32_t exec_path_size = 0;
   int rv = _NSGetExecutablePath(NULL, &exec_path_size);
   if (rv != -1) {
-    fprintf(stderr, "_NSGetExecutablePath: get length failed\n");
-    abort();
+    FatalError("_NSGetExecutablePath: get length failed.");
   }
 
   auto exec_path = std::make_unique<char[]>(exec_path_size);
   rv = _NSGetExecutablePath(exec_path.get(), &exec_path_size);
   if (rv != 0) {
-    fprintf(stderr, "_NSGetExecutablePath: get path failed\n");
-    abort();
+    FatalError("_NSGetExecutablePath: get path failed.");
   }
   sandbox::SeatbeltExecServer::CreateFromArgumentsResult seatbelt =
       sandbox::SeatbeltExecServer::CreateFromArguments(exec_path.get(), argc,
                                                        argv);
   if (seatbelt.sandbox_required) {
     if (!seatbelt.server) {
-      fprintf(stderr, "Failed to create seatbelt sandbox server.\n");
-      abort();
+      FatalError("Failed to create seatbelt sandbox server.");
     }
     if (!seatbelt.server->InitializeSandbox()) {
-      fprintf(stderr, "Failed to initialize sandbox.\n");
-      abort();
+      FatalError("Failed to initialize sandbox.");
     }
   }
 #endif  // defined(HELPER_EXECUTABLE) && !defined(MAS_BUILD)