trace_processor: add support for zero events

Change-Id: I485eb3086db2ac3462921d4517274862a4b98b4e
Bug: 133453890
diff --git a/Android.bp b/Android.bp
index 1d3b600..29c94a4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -3570,6 +3570,7 @@
     "src/trace_processor/string_pool.cc",
     "src/trace_processor/string_table.cc",
     "src/trace_processor/syscall_tracker.cc",
+    "src/trace_processor/systrace_parser.cc",
     "src/trace_processor/systrace_trace_parser.cc",
     "src/trace_processor/table.cc",
     "src/trace_processor/thread_table.cc",