Obsolete the DataUse.MessageSize.<ServiceName> histograms

DataUse.MessageSize.<ServiceName> histogram is recorded for each service.
This histogram is used sparingly. Since there are more services, this
per service histogram is not needed.

Bug: 732638
Change-Id: I0d6a54ec4037da6692d8a5dcb7a537641aa111c1
Reviewed-on: https://chromium-review.googlesource.com/742690
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539912}

components/data_use_measurement/core/data_use_measurement.cc

@@ -394,9 +394,6 @@ void DataUseMeasurement::ReportDataUsageServices(
     DataUseUserData::AppState app_state,
     bool is_connection_cellular,
     int64_t message_size) const {
-  RecordUMAHistogramCount(
-      "DataUse.MessageSize." + DataUseUserData::GetServiceNameAsString(service),
-      message_size);
   if (message_size > 0) {
     IncreaseSparseHistogramByValue(
         GetHistogramName("DataUse.MessageSize.AllServices", dir, app_state,

components/data_use_measurement/core/data_use_measurement.h

@@ -123,9 +123,8 @@ class DataUseMeasurement {
   void ReportServicesMessageSizeUMA(const net::URLRequest& request);
 
   // Records data use histograms of services. It gets the size of exchanged
-  // message, its direction (which is upstream or downstream) and reports to two
-  // histogram groups. DataUse.MessageSize.ServiceName and
-  // DataUse.Services.{Dimensions}. In the second one, services are buckets.
+  // message, its direction (which is upstream or downstream) and reports to the
+  // histogram DataUse.Services.{Dimensions} with, services as the buckets.
   // |app_state| indicates the app state which can be foreground, background, or
   // unknown.
   void ReportDataUsageServices(

components/data_use_measurement/core/data_use_measurement_unittest.cc

@@ -195,8 +195,6 @@ class DataUseMeasurementTest : public testing::Test {
     histogram_tester.ExpectTotalCount("DataUse.TrafficSize.System.Upstream." +
                                           target_dimension + kConnectionType,
                                       1);
-    // One upload and one download message, so total count should be 2.
-    histogram_tester.ExpectTotalCount("DataUse.MessageSize.Suggestions", 2);
   }
 
   DataUseMeasurement* data_use_measurement() { return &data_use_measurement_; }

components/data_use_measurement/core/data_use_network_delegate_unittest.cc

@@ -150,9 +150,8 @@ class DataUseNetworkDelegateTest : public testing::Test {
 
 // This function tests data use measurement for requests by services. it makes a
 // query which is similar to a query of a service, so it should affect
-// DataUse.TrafficSize.System.Dimensions and DataUse.MessageSize.ServiceName
-// histograms. AppState and ConnectionType dimensions are always Foreground and
-// NotCellular respectively.
+// DataUse.TrafficSize.System.Dimensions histogram. AppState and ConnectionType
+// dimensions are always Foreground and NotCellular respectively.
 TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementServiceTest) {
   base::HistogramTester histogram_tester;
 
@@ -165,9 +164,6 @@ TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementServiceTest) {
           .empty());
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.System.Upstream.Foreground.NotCellular", 1);
-  EXPECT_FALSE(histogram_tester
-                   .GetTotalCountsForPrefix("DataUse.MessageSize.Suggestions")
-                   .empty());
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.User.Downstream.Foreground.NotCellular", 0);
   histogram_tester.ExpectTotalCount(
@@ -194,14 +190,13 @@ TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementUserTest) {
       "DataUse.TrafficSize.System.Downstream.Foreground.NotCellular", 0);
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.System.Upstream.Foreground.NotCellular", 0);
-  histogram_tester.ExpectTotalCount("DataUse.MessageSize.Suggestions", 0);
 }
 
 // This function tests data use measurement for requests by services in case the
 // request is redirected once. it makes a query which is similar to a query of a
 // service, so it should affect DataUse.TrafficSize.System.Dimensions and
-// DataUse.MessageSize.ServiceName histograms. AppState and ConnectionType
-// dimensions are always Foreground and NotCellular respectively.
+// histogram. AppState and ConnectionType dimensions are always Foreground and
+// NotCellular respectively.
 TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementServiceTestWithRedirect) {
   base::HistogramTester histogram_tester;
 
@@ -215,9 +210,6 @@ TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementServiceTestWithRedirect) {
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.System.Upstream.Foreground.NotCellular", 2);
   // Two uploads and two downloads message, so totalCount should be 4.
-  EXPECT_FALSE(histogram_tester
-                   .GetTotalCountsForPrefix("DataUse.MessageSize.Suggestions")
-                   .empty());
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.User.Downstream.Foreground.NotCellular", 0);
   histogram_tester.ExpectTotalCount(
@@ -245,7 +237,6 @@ TEST_F(DataUseNetworkDelegateTest, DataUseMeasurementUserTestWithRedirect) {
       "DataUse.TrafficSize.System.Downstream.Foreground.NotCellular", 0);
   histogram_tester.ExpectTotalCount(
       "DataUse.TrafficSize.System.Upstream.Foreground.NotCellular", 0);
-  histogram_tester.ExpectTotalCount("DataUse.MessageSize.Suggestions", 0);
 }
 
 }  // namespace

tools/metrics/histograms/histograms.xml

@@ -14497,6 +14497,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="DataUse.MessageSize" units="bytes">
+  <obsolete>
+    Deprecated 10/2017.
+  </obsolete>
   <owner>amohammadkhan@chromium.org</owner>
   <owner>bengr@chromium.org</owner>
   <summary>