[Tracing] Add metadata filter

chrome/browser/tracing/chrome_tracing_delegate.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 "chrome/browser/tracing/chrome_tracing_delegate.h"
 
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/tracing/crash_service_uploader.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_otr_state.h"
 #include "chrome/common/pref_names.h"
+#include "chrome/common/trace_event_args_whitelist.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/variations/active_field_trials.h"
 #include "content/public/browser/background_tracing_config.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace {
 
 const int kMinDaysUntilNextUpload = 7;
 
 }  // namespace
@@ skipping 115 matching lines @@
   DCHECK(metadata_dict);
   std::vector<std::string> variations;
   variations::GetFieldTrialActiveGroupIdsAsStrings(&variations);
 
   scoped_ptr<base::ListValue> variations_list(new base::ListValue());
   for (const auto& it : variations)
     variations_list->Append(new base::StringValue(it));
 
   metadata_dict->Set("field-trials", variations_list.Pass());
 }
+
+content::MetadataFilterPredicate
+ChromeTracingDelegate::GetMetadataFilterPredicate() {
+  return base::Bind(&IsMetadataWhitelisted);
+}