crash-reporter: Add diagnostics to help diagnose failures in the wild

system_logging_mock.cc

Index: system_logging_mock.cc
diff --git a/system_logging_mock.cc b/system_logging_mock.cc
index a2760e9d55d88faf52d4e10ef2bf3cdfe6016655..1855c2103e41322155568d6ef54f860d350e67cc 100644
--- a/system_logging_mock.cc
+++ b/system_logging_mock.cc
@@ -33,3 +33,6 @@ void SystemLoggingMock::LogError(const char *format, ...) {
   log_ += "\n";
   va_end(vl);
 }
+
+void SystemLoggingMock::set_accumulator(std::string *accumulator) {
+}