Only enable the Dart timeline for benchmarks

services/dart/dart_tracing.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/dart/dart_tracing.h"
 
 #include "dart/runtime/include/dart_tools_api.h"
 #include "mojo/public/cpp/application/application_impl.h"
 
 namespace dart {
 
 void DartTimelineController::Enable(const mojo::String& categories) {
-  // TODO(johnmccutchan): Respect |categories|.
-  EnableAll();
+  if (categories == mojo::String("Dart")) {
+    Dart_GlobalTimelineSetRecordedStreams(DART_TIMELINE_STREAM_DART);
+  } else {
+    // TODO(johnmccutchan): Respect |categories|.
+    EnableAll();
+  }
 }
 
 void DartTimelineController::EnableAll() {
   Dart_GlobalTimelineSetRecordedStreams(DART_TIMELINE_STREAM_ALL |
                                         DART_TIMELINE_STREAM_VM);
 }
 
 void DartTimelineController::Disable() {
   Dart_GlobalTimelineSetRecordedStreams(DART_TIMELINE_STREAM_DISABLE);
 }
@@ skipping 102 matching lines @@
   connection->AddService(this);
 }
 
 void DartTracingImpl::Create(
     mojo::ApplicationConnection* connection,
     mojo::InterfaceRequest<tracing::TraceProvider> request) {
   provider_impl_.Bind(request.Pass());
 }
 
 }  // namespace dart