Uses SNPRINT macro where possible. Otherwise uses #define for format.

runtime/vm/benchmark_test.cc

Index: runtime/vm/benchmark_test.cc
diff --git a/runtime/vm/benchmark_test.cc b/runtime/vm/benchmark_test.cc
index ee3ca574a87d49d1e6df0f6d7637b96a64d0a7e6..c463c8428d9094929dd39e79b36319d860974acc 100644
--- a/runtime/vm/benchmark_test.cc
+++ b/runtime/vm/benchmark_test.cc
@@ -354,12 +354,8 @@ BENCHMARK(Dart2JSCompileAll) {
   char* script = NULL;
   if (dart_root != NULL) {
     HANDLESCOPE(thread);
-    const char* kFormatStr =
-        "import '%s/pkg/compiler/lib/compiler.dart';";
-    intptr_t len = OS::SNPrint(NULL, 0, kFormatStr, dart_root) + 1;
-    script = reinterpret_cast<char*>(malloc(len));
-    EXPECT(script != NULL);
-    OS::SNPrint(script, len, kFormatStr, dart_root);
+    SNPRINT(script, malloc, "import '%s/pkg/compiler/lib/compiler.dart';",
+            dart_root);
     Dart_Handle lib = TestCase::LoadTestScript(
         script,
         reinterpret_cast<Dart_NativeEntryResolver>(NativeResolver));