Add metrics to help measure effects of installing default apps in a profile.

chrome/browser/extensions/crx_installer.cc

 // Copyright (c) 2011 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/extensions/crx_installer.h"
 
 #include <map>
 #include <set>
 
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
 #include "base/stl_util.h"
 #include "base/stringprintf.h"
 #include "base/task.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/convert_user_script.h"
 #include "chrome/browser/extensions/convert_web_app.h"
+#include "chrome/browser/extensions/default_apps_trial.h"
 #include "chrome/browser/extensions/extension_error_reporter.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/browser/web_applications/web_app.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_file_util.h"
 #include "content/browser/browser_thread.h"
 #include "content/browser/user_metrics.h"
@@ skipping 500 matching lines @@
     client_->OnInstallFailure(error);
 
   NotifyCrxInstallComplete();
 }
 
 void CrxInstaller::ReportSuccessFromFileThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   // Tracking number of extensions installed by users
   if (install_cause() == extension_misc::INSTALL_CAUSE_USER_DOWNLOAD) {
-    UserMetrics::RecordAction(
-        UserMetricsAction("Extensions.ExtensionInstalled"));
+    UMA_HISTOGRAM_ENUMERATION("Extensions.ExtensionInstalled", 1, 2);
+
+    static bool default_apps_trial_exists =
+        base::FieldTrialList::TrialExists(kDefaultAppsTrial_Name);
+    if (default_apps_trial_exists) {
+      UMA_HISTOGRAM_ENUMERATION(
+          base::FieldTrial::MakeName("Extensions.ExtensionInstalled",
+                                     kDefaultAppsTrial_Name),
+          1, 2);
+    }
   }
 
   if (!BrowserThread::PostTask(
           BrowserThread::UI, FROM_HERE,
           NewRunnableMethod(this,
                             &CrxInstaller::ReportSuccessFromUIThread)))
     NOTREACHED();
 }
 
 void CrxInstaller::ReportSuccessFromUIThread() {
@@ skipping 29 matching lines @@
   // Some users (such as the download shelf) need to know when a
   // CRXInstaller is done.  Listening for the EXTENSION_* events
   // is problematic because they don't know anything about the
   // extension before it is unpacked, so they can not filter based
   // on the extension.
   NotificationService::current()->Notify(
       chrome::NOTIFICATION_CRX_INSTALLER_DONE,
       Source<CrxInstaller>(this),
       NotificationService::NoDetails());
 }