Convert class for metric field to AutoValue

This reduces the number of static methods for creating fields and allows
us to extend the Field class in future.

Change-Id: Ieaaacddd03b1e04e4e91f000eff950ecb292ec25
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/server/notedb/NoteDbMetrics.java

@@ -45,7 +45,7 @@ class NoteDbMetrics {
 
   @Inject
   NoteDbMetrics(MetricMaker metrics) {
-    Field<NoteDbTable> view = Field.ofEnum(NoteDbTable.class, "table");
+    Field<NoteDbTable> tableField = Field.ofEnum(NoteDbTable.class, "table").build();
 
     updateLatency =
         metrics.newTimer(
@@ -53,7 +53,7 @@ class NoteDbMetrics {
             new Description("NoteDb update latency by table")
                 .setCumulative()
                 .setUnit(Units.MILLISECONDS),
-            view);
+            tableField);
 
     stageUpdateLatency =
         metrics.newTimer(
@@ -61,7 +61,7 @@ class NoteDbMetrics {
             new Description("Latency for staging updates to NoteDb by table")
                 .setCumulative()
                 .setUnit(Units.MICROSECONDS),
-            view);
+            tableField);
 
     readLatency =
         metrics.newTimer(
@@ -69,7 +69,7 @@ class NoteDbMetrics {
             new Description("NoteDb read latency by table")
                 .setCumulative()
                 .setUnit(Units.MILLISECONDS),
-            view);
+            tableField);
 
     parseLatency =
         metrics.newTimer(
@@ -77,6 +77,6 @@ class NoteDbMetrics {
             new Description("NoteDb parse latency by table")
                 .setCumulative()
                 .setUnit(Units.MICROSECONDS),
-            view);
+            tableField);
   }
 }

java/com/google/gerrit/server/notedb/Sequences.java

@@ -95,8 +95,8 @@ public class Sequences {
             new Description("Latency of requesting IDs from repo sequences")
                 .setCumulative()
                 .setUnit(Units.MILLISECONDS),
-            Field.ofEnum(SequenceType.class, "sequence"),
-            Field.ofBoolean("multiple"));
+            Field.ofEnum(SequenceType.class, "sequence").build(),
+            Field.ofBoolean("multiple").build());
   }
 
   public int nextAccountId() {