Add support for the ExperimentalSwReporterEngine field trial.

chrome/browser/safe_browsing/srt_field_trial_win.cc

 // Copyright 2015 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 "chrome/browser/safe_browsing/srt_field_trial_win.h"
 
+#include <sstream>
+
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace {
 
 // Field trial strings.
 const char kSRTPromptTrial[] = "SRTPromptFieldTrial";
 const char kSRTCanaryGroup[] = "SRTCanary";
 const char kSRTPromptOffGroup[] = "Off";
 const char kSRTPromptSeedParam[] = "Seed";
 
 const char kSRTElevationTrial[] = "SRTElevation";
 const char kSRTElevationAsNeededGroup[] = "AsNeeded";
 
 const char kSRTReporterTrial[] = "srt_reporter";
 const char kSRTReporterOffGroup[] = "Off";
 
+const char kSRTStepMetricName[] = "SoftwareReporter.Step";
+
 // The download links of the Software Removal Tool.
 const char kMainSRTDownloadURL[] =
     "https://dl.google.com/dl"
     "/softwareremovaltool/win/chrome_cleanup_tool.exe?chrome-prompt=1";
 const char kCanarySRTDownloadURL[] =
     "https://dl.google.com/dl"
     "/softwareremovaltool/win/c/chrome_cleanup_tool.exe?chrome-prompt=1";
 
 }  // namespace
 
@@ skipping 27 matching lines @@
 std::string GetIncomingSRTSeed() {
   return variations::GetVariationParamValue(kSRTPromptTrial,
                                             kSRTPromptSeedParam);
 }
 
 void RecordSRTPromptHistogram(SRTPromptHistogramValue value) {
   UMA_HISTOGRAM_ENUMERATION("SoftwareReporter.PromptUsage", value,
                             SRT_PROMPT_MAX);
 }
 
-void RecordReporterStepHistogram(SwReporterUmaValue value) {
-  UMA_HISTOGRAM_ENUMERATION("SoftwareReporter.Step", value, SW_REPORTER_MAX);
+void RecordReporterStepHistogram(SwReporterUmaValue value,
+                                 const std::string& suffix) {
+  if (suffix.empty()) {
+    UMA_HISTOGRAM_ENUMERATION(kSRTStepMetricName, value, SW_REPORTER_MAX);
+    return;
+  }
+  UMA_HISTOGRAM_ENUMERATION(
+      base::StringPrintf("%s_%s", kSRTStepMetricName, suffix).c_str(),
+      value, SW_REPORTER_MAX);
 }
 
 }  // namespace safe_browsing