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

runtime/vm/timeline.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <cstdlib>
 
 #include "vm/atomic.h"
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/lockers.h"
@@ skipping 423 matching lines @@
   if ((file_open == NULL) || (file_write == NULL) || (file_close == NULL)) {
     return;
   }
 
   FinishGlobalBlock();
 
   JSONStream js;
   TimelineEventFilter filter;
   PrintJSON(&js, &filter);
 
-  const char* format = "%s/dart-timeline-%" Pd ".json";
   intptr_t pid = OS::ProcessId();
-  intptr_t len = OS::SNPrint(NULL, 0, format, directory, pid);
-  char* filename = reinterpret_cast<char*>(malloc(len + 1));
-  OS::SNPrint(filename, len + 1, format, directory, pid);
+  char* filename = NULL;
+  SNPRINT(filename, malloc, "%s/dart-timeline-%" Pd ".json", directory, pid);
   void* file = (*file_open)(filename, true);
   if (file == NULL) {
     OS::Print("Failed to write timeline file: %s\n", filename);
     free(filename);
     return;
   }
   free(filename);
   (*file_write)(js.buffer()->buf(), js.buffer()->length(), file);
   (*file_close)(file);
 }
@@ skipping 367 matching lines @@
 
 
 TimelineEventBlock* TimelineEventBlockIterator::Next() {
   ASSERT(current_ != NULL);
   TimelineEventBlock* r = current_;
   current_ = current_->next();
   return r;
 }
 
 }  // namespace dart