Extract guts of ChromeStabilityMetricsProvider into helper class

chrome/browser/metrics/chrome_stability_metrics_provider_unittest.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/metrics/chrome_stability_metrics_provider.h"
 
 #include "base/basictypes.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/prefs/testing_pref_service.h"
@@ skipping 15 matching lines @@
 
 #if defined(ENABLE_EXTENSIONS)
 #include "extensions/browser/process_map.h"
 #endif
 
 namespace {
 
 class ChromeStabilityMetricsProviderTest : public testing::Test {
  protected:
   ChromeStabilityMetricsProviderTest() : prefs_(new TestingPrefServiceSimple) {
-    ChromeStabilityMetricsProvider::RegisterPrefs(prefs()->registry());
+    metrics::StabilityMetricsHelper::RegisterPrefs(prefs()->registry());
   }
 
   TestingPrefServiceSimple* prefs() { return prefs_.get(); }
 
  private:
   scoped_ptr<TestingPrefServiceSimple> prefs_;
   content::TestBrowserThreadBundle thread_bundle_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeStabilityMetricsProviderTest);
 };
@@ skipping 113 matching lines @@
   provider.ProvideStabilityMetrics(&system_profile);
 
   EXPECT_EQ(0, system_profile.stability().renderer_crash_count());
   EXPECT_EQ(1, system_profile.stability().extension_renderer_crash_count());
   EXPECT_EQ(
       1, system_profile.stability().extension_renderer_failed_launch_count());
 #endif
 
   profile_manager->DeleteAllTestingProfiles();
 }