Adding UMA to PreviewsDataSavings

components/previews/previews_data_savings.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/previews/previews_data_savings.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "components/data_reduction_proxy/core/common/data_savings_recorder.h"
 
 namespace previews {
 
 PreviewsDataSavings::PreviewsDataSavings(
     data_reduction_proxy::DataSavingsRecorder* data_savings_recorder)
     : data_savings_recorder_(data_savings_recorder) {
   DCHECK(data_savings_recorder);
 }
 
 PreviewsDataSavings::~PreviewsDataSavings() {
   DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 void PreviewsDataSavings::RecordDataSavings(
     const std::string& fully_qualified_domain_name,
     int64_t data_used,
     int64_t original_size) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  data_savings_recorder_->UpdateDataSavings(fully_qualified_domain_name,
-                                            data_used, original_size);
+  // Only record savings when data saver is enabled.
+  if (!data_savings_recorder_->UpdateDataSavings(fully_qualified_domain_name,
+                                                 data_used, original_size)) {
+    // Record metrics in KB for previews with data saver disabled.
+    UMA_HISTOGRAM_COUNTS("Previews.OriginalContentLength.DataSaverDisabled",
+                         original_size >> 10);
+    UMA_HISTOGRAM_COUNTS("Previews.ContentLength.DataSaverDisabled",
+                         data_used >> 10);
+    if (original_size >= data_used) {
+      UMA_HISTOGRAM_COUNTS("Previews.DataSavings.DataSaverDisabled",

[rkaplow, 2016/09/09 13:24:02]

just want you to verify the default max for this macro (1000000) is a reasonable
max for this metric

+                           (original_size - data_used) >> 10);
+      UMA_HISTOGRAM_PERCENTAGE(
+          "Previews.DataSavingsPercent.DataSaverDisabled",
+          (original_size - data_used) * 100 / original_size);
+    } else {
+      UMA_HISTOGRAM_COUNTS("Previews.DataInflation.DataSaverDisabled",
+                           (data_used - original_size) >> 10);
+      UMA_HISTOGRAM_PERCENTAGE(
+          "Previews.DataInflationPercent.DataSaverDisabled",
+          (data_used - original_size) * 100 / data_used);
+    }
+    return;
+  }
+
+  // Record metrics in KB for previews with data saver enabled.
+  UMA_HISTOGRAM_COUNTS("Previews.OriginalContentLength.DataSaverEnabled",
+                       original_size >> 10);
+  UMA_HISTOGRAM_COUNTS("Previews.ContentLength.DataSaverEnabled",
+                       data_used >> 10);
+  if (original_size >= data_used) {
+    UMA_HISTOGRAM_COUNTS("Previews.DataSavings.DataSaverEnabled",
+                         (original_size - data_used) >> 10);
+    UMA_HISTOGRAM_PERCENTAGE("Previews.DataSavingsPercent.DataSaverEnabled",
+                             (original_size - data_used) * 100 / original_size);
+  } else {
+    UMA_HISTOGRAM_COUNTS("Previews.DataInflation.DataSaverEnabled",
+                         (data_used - original_size) >> 10);
+    UMA_HISTOGRAM_PERCENTAGE("Previews.DataInflationPercent.DataSaverEnabled",
+                             (data_used - original_size) * 100 / data_used);
+  }
 }
 
 }  // namespace previews