[SPARK-7046] Remove InputMetrics from BlockResult

The BlockResult class originally contained an InputMetrics object so that InputMetrics could
directly be used as the InputMetrics for the whole task. Now we copy the fields out of here, and
the presence of this object is confusing because it's only a partial input metrics (it doesn't
include the records read). Because this object is no longer useful (and is confusing), it should
be removed.

core/src/main/scala/org/apache/spark/CacheManager.scala

@@ -44,10 +44,9 @@ private[spark] class CacheManager(blockManager: BlockManager) extends Logging {
     blockManager.get(key) match {
       case Some(blockResult) =>
         // Partition is already materialized, so just return its values
-        val inputMetrics = blockResult.inputMetrics
         val existingMetrics = context.taskMetrics
-          .getInputMetricsForReadMethod(inputMetrics.readMethod)
-        existingMetrics.incBytesRead(inputMetrics.bytesRead)
+          .getInputMetricsForReadMethod(blockResult.readMethod)
+        existingMetrics.incBytesRead(blockResult.bytes)
 
         val iter = blockResult.data.asInstanceOf[Iterator[T]]
         new InterruptibleIterator[T](context, iter) {

core/src/main/scala/org/apache/spark/storage/BlockManager.scala

@@ -50,11 +50,8 @@ private[spark] case class ArrayValues(buffer: Array[Any]) extends BlockValues
 /* Class for returning a fetched block and associated metrics. */
 private[spark] class BlockResult(
     val data: Iterator[Any],
-    readMethod: DataReadMethod.Value,
-    bytes: Long) {
-  val inputMetrics = new InputMetrics(readMethod)
-  inputMetrics.incBytesRead(bytes)
-}
+    val readMethod: DataReadMethod.Value,
+    val bytes: Long)
 
 /**
  * Manager running on every node (driver and executors) which provides interfaces for putting and

core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala

@@ -428,19 +428,19 @@ class BlockManagerSuite extends FunSuite with Matchers with BeforeAndAfterEach
     val list1Get = store.get("list1")
     assert(list1Get.isDefined, "list1 expected to be in store")
     assert(list1Get.get.data.size === 2)
-    assert(list1Get.get.inputMetrics.bytesRead === list1SizeEstimate)
-    assert(list1Get.get.inputMetrics.readMethod === DataReadMethod.Memory)
+    assert(list1Get.get.bytes === list1SizeEstimate)
+    assert(list1Get.get.readMethod === DataReadMethod.Memory)
     val list2MemoryGet = store.get("list2memory")
     assert(list2MemoryGet.isDefined, "list2memory expected to be in store")
     assert(list2MemoryGet.get.data.size === 3)
-    assert(list2MemoryGet.get.inputMetrics.bytesRead === list2SizeEstimate)
-    assert(list2MemoryGet.get.inputMetrics.readMethod === DataReadMethod.Memory)
+    assert(list2MemoryGet.get.bytes === list2SizeEstimate)
+    assert(list2MemoryGet.get.readMethod === DataReadMethod.Memory)
     val list2DiskGet = store.get("list2disk")
     assert(list2DiskGet.isDefined, "list2memory expected to be in store")
     assert(list2DiskGet.get.data.size === 3)
     // We don't know the exact size of the data on disk, but it should certainly be > 0.
-    assert(list2DiskGet.get.inputMetrics.bytesRead > 0)
-    assert(list2DiskGet.get.inputMetrics.readMethod === DataReadMethod.Disk)
+    assert(list2DiskGet.get.bytes > 0)
+    assert(list2DiskGet.get.readMethod === DataReadMethod.Disk)
   }
 
   test("in-memory LRU storage") {