Use std::string_view in EventLogger

Change-Id: If23504e146826f143220b031a5fbc2be2013d127

internal/ceres/event_logger.cc

diff --git a/internal/ceres/event_logger.cc b/internal/ceres/event_logger.cc
index 31049a5..6cdfec7 100644
--- a/internal/ceres/event_logger.cc
+++ b/internal/ceres/event_logger.cc
@@ -31,6 +31,7 @@
 #include "ceres/event_logger.h"
 
 #include <string>
+#include <string_view>
 
 #include "absl/log/log.h"
 #include "absl/log/vlog_is_on.h"
@@ -40,7 +41,7 @@
 
 namespace ceres::internal {
 
-EventLogger::EventLogger(const std::string& logger_name)
+EventLogger::EventLogger(std::string_view logger_name)
     : start_time_(absl::Now()) {
   if (!VLOG_IS_ON(3)) {
     return;
@@ -60,7 +61,7 @@
   VLOG(3) << "\n" << events_ << "\n";
 }
 
-void EventLogger::AddEvent(const std::string& event_name) {
+void EventLogger::AddEvent(std::string_view event_name) {
   if (!VLOG_IS_ON(3)) {
     return;
   }

internal/ceres/event_logger.h

diff --git a/internal/ceres/event_logger.h b/internal/ceres/event_logger.h
index d01119f..5f6c275 100644
--- a/internal/ceres/event_logger.h
+++ b/internal/ceres/event_logger.h
@@ -32,6 +32,7 @@
 #define CERES_INTERNAL_EVENT_LOGGER_H_
 
 #include <string>
+#include <string_view>
 
 #include "absl/time/time.h"
 #include "ceres/internal/disable_warnings.h"
@@ -65,9 +66,9 @@
 //     Total:  time3  time1 + time2 + time3;
 class CERES_NO_EXPORT EventLogger {
  public:
-  explicit EventLogger(const std::string& logger_name);
+  explicit EventLogger(std::string_view logger_name);
   ~EventLogger();
-  void AddEvent(const std::string& event_name);
+  void AddEvent(std::string_view event_name);
 
  private:
   const absl::Time start_time_;