[SPARK-14596][SQL] Remove not used SqlNewHadoopRDD and some more unused imports

## What changes were proposed in this pull request?

Old `HadoopFsRelation` API includes `buildInternalScan()` which uses `SqlNewHadoopRDD` in `ParquetRelation`.
Because now the old API is removed, `SqlNewHadoopRDD` is not used anymore.

So, this PR removes `SqlNewHadoopRDD` and several unused imports.

This was discussed in https://github.com/apache/spark/pull/12326.

## How was this patch tested?

Several related existing unit tests and `sbt scalastyle`.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #12354 from HyukjinKwon/SPARK-14596.

2 files changed, 6 insertions, 8 deletions

diff --git a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
index 08db96edd6..ac5ba9e79f 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -213,15 +213,13 @@ class HadoopRDD[K, V](
       logInfo("Input split: " + split.inputSplit)
       val jobConf = getJobConf()
 
-      // TODO: there is a lot of duplicate code between this and NewHadoopRDD and SqlNewHadoopRDD
-
       val inputMetrics = context.taskMetrics().registerInputMetrics(DataReadMethod.Hadoop)
       val existingBytesRead = inputMetrics.bytesRead
 
       // Sets the thread local variable for the file's name
       split.inputSplit.value match {
-        case fs: FileSplit => SqlNewHadoopRDDState.setInputFileName(fs.getPath.toString)
-        case _ => SqlNewHadoopRDDState.unsetInputFileName()
+        case fs: FileSplit => InputFileNameHolder.setInputFileName(fs.getPath.toString)
+        case _ => InputFileNameHolder.unsetInputFileName()
       }
 
       // Find a function that will return the FileSystem bytes read by this thread. Do this before
@@ -271,7 +269,7 @@ class HadoopRDD[K, V](
 
       override def close() {
         if (reader != null) {
-          SqlNewHadoopRDDState.unsetInputFileName()
+          InputFileNameHolder.unsetInputFileName()
           // Close the reader and release it. Note: it's very important that we don't close the
           // reader more than once, since that exposes us to MAPREDUCE-5918 when running against
           // Hadoop 1.x and older Hadoop 2.x releases. That bug can lead to non-deterministic
diff --git a/core/src/main/scala/org/apache/spark/rdd/SqlNewHadoopRDDState.scala b/core/src/main/scala/org/apache/spark/rdd/InputFileNameHolder.scala
index 3f15fff793..108e9d2558 100644
--- a/core/src/main/scala/org/apache/spark/rdd/SqlNewHadoopRDDState.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/InputFileNameHolder.scala
@@ -20,10 +20,10 @@ package org.apache.spark.rdd
 import org.apache.spark.unsafe.types.UTF8String
 
 /**
- * State for SqlNewHadoopRDD objects. This is split this way because of the package splits.
- * TODO: Move/Combine this with org.apache.spark.sql.datasources.SqlNewHadoopRDD
+ * This holds file names of the current Spark task. This is used in HadoopRDD,
+ * FileScanRDD and InputFileName function in Spark SQL.
  */
-private[spark] object SqlNewHadoopRDDState {
+private[spark] object InputFileNameHolder {
   /**
    * The thread variable for the name of the current file being read. This is used by
    * the InputFileName function in Spark SQL.