Merge pull request #12855 from vjpai/new_const

Add some const

test/cpp/end2end/async_end2end_test.cc

@@ -223,11 +223,8 @@ class TestScenario {
   bool disable_blocking;
   bool inproc;
   bool health_check_service;
-  // Although the below grpc::string's are logically const, we can't declare
-  // them const because of a limitation in the way old compilers (e.g., gcc-4.4)
-  // manage vector insertion using a copy constructor
-  grpc::string credentials_type;
-  grpc::string message_content;
+  const grpc::string credentials_type;
+  const grpc::string message_content;
 };
 
 static std::ostream& operator<<(std::ostream& out,

test/cpp/end2end/end2end_test.cc

@@ -198,10 +198,7 @@ class TestScenario {
   void Log() const;
   bool use_proxy;
   bool inproc;
-  // Although the below grpc::string is logically const, we can't declare
-  // them const because of a limitation in the way old compilers (e.g., gcc-4.4)
-  // manage vector insertion using a copy constructor
-  grpc::string credentials_type;
+  const grpc::string credentials_type;
 };
 
 static std::ostream& operator<<(std::ostream& out,