Revamp the MigrateBrowserPrefs and MigrateUserPrefs code.

chrome/browser/profiles/profile_impl.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 "chrome/browser/profiles/profile_impl.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 837 matching lines @@
 }
 
 void ProfileImpl::OnPrefsLoaded(bool success) {
   TRACE_EVENT0("browser", "ProfileImpl::OnPrefsLoaded")
   if (!success) {
     if (delegate_)
       delegate_->OnProfileCreated(this, false, false);
     return;
   }
 
-  // TODO(mirandac): remove migration code after 6 months (crbug.com/69995).
+  // Migrate all obsolete prefs.

[gab, 2015/02/20 20:33:57]

rm "all" (it's implicit IMO)

PS: I like "obsolete" perhaps add that to the migration method's names? e.g.
MigrateObsoleteBrowserPrefs() and MigrateObsoleteProfilePrefs() -- oh yea, also,
I prefer ProfilePrefs to UserPrefs as it's more explicit (i.e. a user can have
multiple profiles).

[rkaplow, 2015/02/20 21:58:08]

Seems fine. Note that some of the work is done by names that mirror the current
name, eg. autofill::AutofillManager::MigrateUserPrefs

In the long run those will go away so it seems fine for a temporary discrepancy.

   if (g_browser_process->local_state())
     chrome::MigrateBrowserPrefs(this, g_browser_process->local_state());
-  // TODO(ivankr): remove cleanup code eventually (crbug.com/165672).
   chrome::MigrateUserPrefs(this);
 
   // |kSessionExitType| was added after |kSessionExitedCleanly|. If the pref
   // value is empty fallback to checking for |kSessionExitedCleanly|.
   const std::string exit_type_pref_value(
       prefs_->GetString(prefs::kSessionExitType));
   if (exit_type_pref_value.empty()) {
     last_session_exit_type_ =
         prefs_->GetBoolean(prefs::kSessionExitedCleanly) ?
           EXIT_NORMAL : EXIT_CRASHED;
@@ skipping 451 matching lines @@
 ProfileImpl::CreateDomainReliabilityMonitor(PrefService* local_state) {
   domain_reliability::DomainReliabilityService* service =
       domain_reliability::DomainReliabilityServiceFactory::GetInstance()->
           GetForBrowserContext(this);
   if (!service)
     return scoped_ptr<domain_reliability::DomainReliabilityMonitor>();
 
   return service->CreateMonitor(
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 }