Rework UMAHistogramHelper and StatisticsDeltaReader into [Chrome]HistogramTester.

chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc

Index: chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc
diff --git a/chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc b/chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc
index ce4fec8e371513f86397654fc82ff472a3020eed..19dc37c95b230aaad950151eb1fd8ecf58e75498 100644
--- a/chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc
+++ b/chrome/browser/ui/views/profiles/profile_chooser_view_browsertest.cc
@@ -8,6 +8,7 @@
 #include "base/path_service.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/histogram_tester.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/profiles/profile_metrics.h"
@@ -25,7 +26,6 @@
 #include "chrome/test/base/test_switches.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile_manager.h"
-#include "chrome/test/base/uma_histogram_helper.h"
 #include "components/signin/core/common/profile_management_switches.h"
 #include "content/public/test/test_utils.h"
 #include "ui/views/controls/button/label_button.h"
@@ -86,7 +86,6 @@ void ProfileChooserViewBrowserTest::OpenProfileChooserView() {
 // TODO(mlerman): Re-enable the test to MAYBE_ViewProfileUMA once there is a
 // launch plan for EnableAccountConsistency.
 IN_PROC_BROWSER_TEST_F(ProfileChooserViewBrowserTest, DISABLED_ViewProfileUMA) {
-  // If multiprofile mode is not enabled, you can't switch between profiles.
   if (!profiles::IsMultipleProfilesEnabled())
     return;