Add static method to generated code to return fully qualified protobuf service name.

src/compiler/cpp_generator.cc

@@ -804,6 +804,13 @@ void PrintHeaderService(grpc_generator::Printer *printer,
                  " public:\n");
   printer->Indent();
 
+  // Service metadata
+  printer->Print(
+      *vars,
+      "static constexpr char const* service_full_name() {\n"
+      "  return \"$Package$$Service$\";\n"
+      "}\n");
+
   // Client side
   printer->Print(
       "class StubInterface {\n"

test/cpp/codegen/compiler_test_golden

@@ -69,6 +69,9 @@ namespace testing {
 // ServiceA leading comment 1
 class ServiceA final {
  public:
+  static constexpr char const* service_full_name() {
+    return "grpc.testing.ServiceA";
+  }
   class StubInterface {
    public:
     virtual ~StubInterface() {}
@@ -373,6 +376,9 @@ class ServiceA final {
 // ServiceB leading comment 1
 class ServiceB final {
  public:
+  static constexpr char const* service_full_name() {
+    return "grpc.testing.ServiceB";
+  }
   class StubInterface {
    public:
     virtual ~StubInterface() {}