Merge histograms from providers into StatisticsRecorder for display.

components/metrics/file_metrics_provider.cc

 // Copyright 2016 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 "components/metrics/file_metrics_provider.h"
 
 #include "base/command_line.h"
 #include "base/files/file.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
@@ skipping 104 matching lines @@
  private:
   DISALLOW_COPY_AND_ASSIGN(SourceInfo);
 };
 
 FileMetricsProvider::FileMetricsProvider(
     const scoped_refptr<base::TaskRunner>& task_runner,
     PrefService* local_state)
     : task_runner_(task_runner),
       pref_service_(local_state),
       weak_factory_(this) {
+  base::StatisticsRecorder::RegisterHistogramProvider(
+      weak_factory_.GetWeakPtr());
 }
 
 FileMetricsProvider::~FileMetricsProvider() {}
 
 void FileMetricsProvider::RegisterSource(const base::FilePath& path,
                                          SourceType type,
                                          SourceAssociation source_association,
                                          const base::StringPiece prefs_key) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
@@ skipping 380 matching lines @@
       DCHECK(!source->allocator);
       RecordSourceAsRead(source);
       DeleteFileAsync(source->path);
       sources_for_previous_run_.erase(temp);
     }
   }
 
   return !sources_for_previous_run_.empty();
 }
 
-void FileMetricsProvider::MergeHistogramDeltas() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  // Measure the total time spent processing all sources as well as the time
-  // per individual file. This method is called on the UI thread so it's
-  // important to know how much total "jank" may be introduced.
-  SCOPED_UMA_HISTOGRAM_TIMER("UMA.FileMetricsProvider.SnapshotTime.Total");
-
-  for (std::unique_ptr<SourceInfo>& source : sources_mapped_) {
-    SCOPED_UMA_HISTOGRAM_TIMER("UMA.FileMetricsProvider.SnapshotTime.File");
-    MergeHistogramDeltasFromSource(source.get());
-  }
-}
-
 void FileMetricsProvider::RecordInitialHistogramSnapshots(
     base::HistogramSnapshotManager* snapshot_manager) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Measure the total time spent processing all sources as well as the time
   // per individual file. This method is called during startup and thus blocks
   // the initial showing of the browser window so it's important to know the
   // total delay.
   SCOPED_UMA_HISTOGRAM_TIMER(
       "UMA.FileMetricsProvider.InitialSnapshotTime.Total");
 
   for (const std::unique_ptr<SourceInfo>& source : sources_for_previous_run_) {
     SCOPED_UMA_HISTOGRAM_TIMER(
         "UMA.FileMetricsProvider.InitialSnapshotTime.File");
 
     // The source needs to have an allocator attached to it in order to read
     // histograms out of it.
     DCHECK(!source->read_complete);
     DCHECK(source->allocator);
 
     // Dump all histograms contained within the source to the snapshot-manager.
     RecordHistogramSnapshotsFromSource(snapshot_manager, source.get());
 
     // Update the last-seen time so it isn't read again unless it changes.
     RecordSourceAsRead(source.get());
   }
 }
 
+void FileMetricsProvider::MergeHistogramDeltas() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // Measure the total time spent processing all sources as well as the time
+  // per individual file. This method is called on the UI thread so it's
+  // important to know how much total "jank" may be introduced.
+  SCOPED_UMA_HISTOGRAM_TIMER("UMA.FileMetricsProvider.SnapshotTime.Total");
+
+  for (std::unique_ptr<SourceInfo>& source : sources_mapped_) {
+    SCOPED_UMA_HISTOGRAM_TIMER("UMA.FileMetricsProvider.SnapshotTime.File");
+    MergeHistogramDeltasFromSource(source.get());
+  }
+}
+
 }  // namespace metrics