Soong: Fix the package name in metrics.proto file

The metrics.proto needs to be imported to Google3 in order to unmarshal
the build metrics data from bigstore. Cleaned up the enum names to use
the Camel naming convention and renamed the build_metrics to
soong_metrics to be more specific to soong and to allow quering
soong_metrics files from bigstore.

Bug: b/135280521
Test: lunch andf m -j. Checked if soong_metrics was generated correctly
      by using printproto command.

Change-Id: I998c8d05db592e94a653d6ca32250b80df3c9b21
diff --git a/ui/metrics/time.go b/ui/metrics/time.go
index 7e8801a..b8baf16 100644
--- a/ui/metrics/time.go
+++ b/ui/metrics/time.go
@@ -30,7 +30,7 @@
 
 type TimeTracer interface {
 	Begin(name, desc string, thread tracer.Thread)
-	End(thread tracer.Thread) metrics_proto.PerfInfo
+	End(thread tracer.Thread) soong_metrics_proto.PerfInfo
 }
 
 type timeTracerImpl struct {
@@ -51,11 +51,11 @@
 	t.activeEvents = append(t.activeEvents, timeEvent{name: name, desc: desc, atNanos: atNanos})
 }
 
-func (t *timeTracerImpl) End(thread tracer.Thread) metrics_proto.PerfInfo {
+func (t *timeTracerImpl) End(thread tracer.Thread) soong_metrics_proto.PerfInfo {
 	return t.endAt(t.now())
 }
 
-func (t *timeTracerImpl) endAt(atNanos uint64) metrics_proto.PerfInfo {
+func (t *timeTracerImpl) endAt(atNanos uint64) soong_metrics_proto.PerfInfo {
 	if len(t.activeEvents) < 1 {
 		panic("Internal error: No pending events for endAt to end!")
 	}
@@ -63,7 +63,7 @@
 	t.activeEvents = t.activeEvents[:len(t.activeEvents)-1]
 	realTime := atNanos - lastEvent.atNanos
 
-	return metrics_proto.PerfInfo{
+	return soong_metrics_proto.PerfInfo{
 		Desc:      &lastEvent.desc,
 		Name:      &lastEvent.name,
 		StartTime: &lastEvent.atNanos,