Delete base/prefs and update callers to use components.

ios/chrome/browser/metrics/ios_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 "ios/chrome/browser/metrics/ios_chrome_stability_metrics_provider.h"
 
 #include "base/macros.h"
-#include "base/prefs/pref_service.h"
-#include "base/prefs/scoped_user_pref_update.h"
-#include "base/prefs/testing_pref_service.h"
 #include "components/metrics/proto/system_profile.pb.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/scoped_user_pref_update.h"
+#include "components/prefs/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 class IOSChromeStabilityMetricsProviderTest : public testing::Test {
  protected:
   IOSChromeStabilityMetricsProviderTest()
       : prefs_(new TestingPrefServiceSimple) {
     metrics::StabilityMetricsHelper::RegisterPrefs(prefs()->registry());
   }
@@ skipping 54 matching lines @@
   provider.OnRecordingEnabled();
   provider.LogRendererCrash();
 
   system_profile.Clear();
   provider.ProvideStabilityMetrics(&system_profile);
 
   EXPECT_EQ(1, system_profile.stability().renderer_crash_count());
   EXPECT_EQ(0, system_profile.stability().renderer_failed_launch_count());
   EXPECT_EQ(0, system_profile.stability().extension_renderer_crash_count());
 }