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..04ce853b7e74f65fdd57854f0804e7ada339bbba 100644
--- a/system_logging_mock.cc
+++ b/system_logging_mock.cc
@@ -33,3 +33,10 @@ void SystemLoggingMock::LogError(const char *format, ...) {
   log_ += "\n";
   va_end(vl);
 }
+
+void SystemLoggingMock::set_accumulating(bool value) {
+}
+
+std::string SystemLoggingMock::get_accumulator() {
+  return "";
+}