Refactoring device name utils (#11797)

* remove duplicated code for full_name and legacy_name for DeviceNameUtils

* replace tabs

* Real->Device

tensorflow/core/util/device_name_utils.cc

@@ -85,28 +85,29 @@ static bool ConsumeNumber(StringPiece* in, int* val) {
   }
 }
 
-/* static */
-string DeviceNameUtils::FullName(const string& job, int replica, int task,
-                                 const string& type, int id) {
+// Returns a fully qualified device name given the parameters.
+static string DeviceName(const string& job, int replica, int task,
+                         const string& device_prefix, const string& device_type,
+                         int id) {
   CHECK(IsJobName(job)) << job;
   CHECK_LE(0, replica);
   CHECK_LE(0, task);
-  CHECK(!type.empty());
+  CHECK(!device_type.empty());
   CHECK_LE(0, id);
   return strings::StrCat("/job:", job, "/replica:", replica, "/task:", task,
-                         "/device:", type, ":", id);
+                         device_prefix, device_type, ":", id);
+}
+
+/* static */
+string DeviceNameUtils::FullName(const string& job, int replica, int task,
+                                 const string& type, int id) {
+  return DeviceName(job, replica, task, "/device:", type, id);
 }
 
 /* static */
 string DeviceNameUtils::LegacyName(const string& job, int replica, int task,
                                    const string& type, int id) {
-  CHECK(IsJobName(job)) << job;
-  CHECK_LE(0, replica);
-  CHECK_LE(0, task);
-  CHECK(!type.empty());
-  CHECK_LE(0, id);
-  return strings::StrCat("/job:", job, "/replica:", replica, "/task:", task,
-                         "/", str_util::Lowercase(type), ":", id);
+  return DeviceName(job, replica, task, "/", str_util::Lowercase(type), id);
 }
 
 bool DeviceNameUtils::ParseFullName(StringPiece fullname, ParsedName* p) {