Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/metrics/metrics_log_unittest.cc

 // Copyright (c) 2012 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 <string>
 
 #include "base/basictypes.h"
 #include "base/port.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 32 matching lines @@
   {37, 43},
   {13, 47},
   {23, 17}
 };
 
 class TestMetricsLog : public MetricsLog {
  public:
   TestMetricsLog(const std::string& client_id, int session_id)
       : MetricsLog(client_id, session_id),
         brand_for_testing_(kBrandForTesting) {
-          chrome::RegisterLocalState(prefs_.registry(), &prefs_);
+    chrome::RegisterLocalState(&prefs_, prefs_.registry());
 
 #if defined(OS_CHROMEOS)
     prefs_.SetInteger(prefs::kStabilityChildProcessCrashCount, 10);
     prefs_.SetInteger(prefs::kStabilityOtherUserCrashCount, 11);
     prefs_.SetInteger(prefs::kStabilityKernelCrashCount, 12);
     prefs_.SetInteger(prefs::kStabilitySystemUncleanShutdownCount, 13);
 #endif  // OS_CHROMEOS
   }
   virtual ~TestMetricsLog() {}
 
@@ skipping 250 matching lines @@
   EXPECT_NE(std::string::npos,
             encoded.find(" childprocesscrashcount=\"10\""));
   EXPECT_EQ(std::string::npos,
             encoded.find(" otherusercrashcount="));
   EXPECT_EQ(std::string::npos,
             encoded.find(" kernelcrashcount="));
   EXPECT_EQ(std::string::npos,
             encoded.find(" systemuncleanshutdowns="));
 }
 #endif  // OS_CHROMEOS