Log pref file size histogram on read rather than on write.

base/prefs/json_pref_store.cc

 // Copyright (c) 2012 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 "base/prefs/json_pref_store.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/memory/ref_counted.h"
-#include "base/metrics/histogram.h"
 #include "base/prefs/pref_filter.h"
 #include "base/sequenced_task_runner.h"
 #include "base/strings/string_util.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/values.h"
 
 // Result returned from internal read tasks.
 struct JsonPrefStore::ReadResult {
  public:
@@ skipping 65 matching lines @@
 }
 
 scoped_ptr<JsonPrefStore::ReadResult> ReadPrefsFromDisk(
     const base::FilePath& path,
     const base::FilePath& alternate_path) {
   if (!base::PathExists(path) && !alternate_path.empty() &&
       base::PathExists(alternate_path)) {
     base::Move(alternate_path, path);
   }
 
+  std::string histogram_suffix;
+  base::ReplaceChars(path.BaseName().MaybeAsASCII(), " ", "_",
+                     &histogram_suffix);
+
   int error_code;
   std::string error_msg;
   scoped_ptr<JsonPrefStore::ReadResult> read_result(
       new JsonPrefStore::ReadResult);
-  JSONFileValueSerializer serializer(path);
+  JSONFileValueSerializer serializer(path, histogram_suffix);
   read_result->value.reset(serializer.Deserialize(&error_code, &error_msg));
   read_result->error =
       HandleReadErrors(read_result->value.get(), path, error_code, error_msg);
   read_result->no_dir = !base::PathExists(path.DirName());
   return read_result.Pass();
 }
 
 }  // namespace
 
 // static
@@ skipping 255 matching lines @@
 }
 
 bool JsonPrefStore::SerializeData(std::string* output) {
   DCHECK(CalledOnValidThread());
 
   if (pref_filter_)
     pref_filter_->FilterSerializeData(prefs_.get());
 
   JSONStringValueSerializer serializer(output);
   serializer.set_pretty_print(true);
-  bool result = serializer.Serialize(*prefs_);
-
-  if (result) {
-    std::string spaceless_basename;
-    base::ReplaceChars(path_.BaseName().MaybeAsASCII(), " ", "_",
-                       &spaceless_basename);
-
-    // The histogram below is an expansion of the UMA_HISTOGRAM_COUNTS_10000
-    // macro adapted to allow for a dynamically suffixed histogram name.
-    // Note: The factory creates and owns the histogram.
-    base::HistogramBase* histogram =
-        base::LinearHistogram::FactoryGet(
-            "Settings.JsonDataSizeKilobytes." + spaceless_basename,
-            1,
-            10000,
-            50,
-            base::HistogramBase::kUmaTargetedHistogramFlag);
-    histogram->Add(static_cast<int>(output->size()) / 1024);
-  }
-
-  return result;
+  return serializer.Serialize(*prefs_);
 }
 
 void JsonPrefStore::FinalizeFileRead(bool initialization_successful,
                                      scoped_ptr<base::DictionaryValue> prefs,
                                      bool schedule_write) {
   DCHECK(CalledOnValidThread());
 
   filtering_in_progress_ = false;
 
   if (!initialization_successful) {
@@ skipping 12 matching lines @@
 
   if (error_delegate_ && read_error_ != PREF_READ_ERROR_NONE)
     error_delegate_->OnError(read_error_);
 
   FOR_EACH_OBSERVER(PrefStore::Observer,
                     observers_,
                     OnInitializationCompleted(true));
 
   return;
 }