Adding UMA to PreviewsDataSavings

components/previews/previews_data_savings.cc

Index: components/previews/previews_data_savings.cc
diff --git a/components/previews/previews_data_savings.cc b/components/previews/previews_data_savings.cc
index 36cfab85087e72a5329e58fcf06442296dd59f9e..b2b6ff307df7d01dd5ae8477b5a565900f1c68d0 100644
--- a/components/previews/previews_data_savings.cc
+++ b/components/previews/previews_data_savings.cc
@@ -19,15 +19,53 @@ PreviewsDataSavings::PreviewsDataSavings(
 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