[machine] Process OS and Cores Standalone fields in machineserver.

Those dimensions, computed by TMM independently of Swarming, now show up
for Macs on machines.skia.org.

Change-Id: I6e9d06715de2e808bb5e2dab05a3d51b1184dcea
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/558156
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Erik Rose <erikrose@google.com>
diff --git a/machine/go/machine/machine.go b/machine/go/machine/machine.go
index 2bbcb97..e386cc9 100644
--- a/machine/go/machine/machine.go
+++ b/machine/go/machine/machine.go
@@ -53,6 +53,7 @@
 	DimChromeOSChannel        = "chromeos_channel"
 	DimChromeOSMilestone      = "chromeos_milestone"
 	DimChromeOSReleaseVersion = "release_version"
+	DimCores                  = "cores"
 
 	BadBatteryLevel = -99
 )
diff --git a/machine/go/machine/processor/impl.go b/machine/go/machine/processor/impl.go
index dae0b10..71cff6b 100644
--- a/machine/go/machine/processor/impl.go
+++ b/machine/go/machine/processor/impl.go
@@ -323,6 +323,8 @@
 	ret.Battery = 0
 	ret.Temperature = nil
 	ret.Dimensions[machine.DimID] = []string{event.Host.Name}
+	ret.Dimensions[machine.DimCores] = []string{strconv.Itoa(event.Standalone.Cores)}
+	ret.Dimensions[machine.DimOS] = event.Standalone.OSVersions
 	ret = handleGeneralFields(ctx, ret, event)
 	ret = handleRecoveryMode(ctx, previous, ret, false, "")
 	return ret
diff --git a/machine/go/test_machine_monitor/machine/machine.go b/machine/go/test_machine_monitor/machine/machine.go
index 1a9d4e5..8d84838 100644
--- a/machine/go/test_machine_monitor/machine/machine.go
+++ b/machine/go/test_machine_monitor/machine/machine.go
@@ -209,7 +209,7 @@
 		}
 
 	default:
-		sklog.Error("Unhandled type of machine.AttachedDevice.")
+		sklog.Errorf("Unhandled type of machine.AttachedDevice: %s", m.description.AttachedDevice)
 
 	}