trace_processor: add support for creating protos from SQL

Implements go/perfetto-metrics-sql-proto for trace processor.

Context: go/perfetto-metrics
Bug: 129747127
Change-Id: Id8516f7478850009baee117a988b9d9598a15e49
diff --git a/Android.bp b/Android.bp
index 3a0c475..05add93 100644
--- a/Android.bp
+++ b/Android.bp
@@ -3226,6 +3226,7 @@
     "src/trace_processor/heap_profile_mapping_table.cc",
     "src/trace_processor/heap_profile_tracker.cc",
     "src/trace_processor/instants_table.cc",
+    "src/trace_processor/metrics/descriptors.cc",
     "src/trace_processor/metrics/metrics.cc",
     "src/trace_processor/process_table.cc",
     "src/trace_processor/process_tracker.cc",