Constructor without callback added to ProfilerMetricsProvider.

components/metrics/profiler/profiler_metrics_provider.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_METRICS_PROFILER_PROFILER_METRICS_PROVIDER_H_
 #define COMPONENTS_METRICS_PROFILER_PROFILER_METRICS_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
 
 namespace tracked_objects {
 struct ProcessDataSnapshot;
 }
 
 namespace metrics {
 
 // ProfilerMetricsProvider is responsible for filling out the |profiler_event|
 // section of the UMA proto.
 class ProfilerMetricsProvider : public MetricsProvider {
  public:
   explicit ProfilerMetricsProvider(
       const base::Callback<void(bool*)>& cellular_callback);
+  // Creates profiler metrics provider with a null callback.
+  ProfilerMetricsProvider();
   ~ProfilerMetricsProvider() override;
 
   // MetricsDataProvider:
   void ProvideGeneralMetrics(ChromeUserMetricsExtension* uma_proto) override;
 
   // Records the passed profiled data, which should be a snapshot of the
   // browser's profiled performance during startup for a single process.
   void RecordProfilerData(
       const tracked_objects::ProcessDataSnapshot& process_data,
       int process_type);
@@ skipping 13 matching lines @@
 
   // Callback function used to get current network connection type.
   base::Callback<void(bool*)> cellular_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfilerMetricsProvider);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_PROFILER_PROFILER_METRICS_PROVIDER_H_