:context_util_test depends on :span_context. (#262)

g-easy · web-flow · commit 2752d1e7eb48 · 2018-12-19T15:31:05.000+11:00
Previously it was picking it up transitively.
diff --git a/opencensus/trace/BUILD b/opencensus/trace/BUILD
@@ -199,6 +199,7 @@ cc_test(
     copts = TEST_COPTS,
     deps = [
         ":context_util",
+        ":span_context",
         ":trace",
         ":with_span",
         "//opencensus/context",
