ART: Use enums in Trace

Move away from booleans. Will make introduction of streaming mode
a bit easier / obvious.

Change-Id: Id7ae92f6b97f627e848510d473931537d7db0db8
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index c462153..c17c0f3 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1012,8 +1012,8 @@
                  -1,
                  static_cast<int>(method_trace_file_size_),
                  0,
-                 false,
-                 false,
+                 Trace::TraceOutputMode::kFile,
+                 Trace::TraceMode::kMethodTracing,
                  0);
   }