Roll Chrome into Mojo.

base/prefs/pref_service.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 "base/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 35 matching lines @@
     base::Callback<void(PersistentPrefStore::PrefReadError)>
         read_error_callback,
     bool async)
     : pref_notifier_(pref_notifier),
       pref_value_store_(pref_value_store),
       pref_registry_(pref_registry),
       user_pref_store_(user_prefs),
       read_error_callback_(read_error_callback) {
   pref_notifier_->SetPrefService(this);
 
+  // TODO(battre): This is a check for crbug.com/435208 to make sure that
+  // access violations are caused by a use-after-free bug and not by an
+  // initialization bug.
+  CHECK(pref_registry_);
+  CHECK(pref_value_store_);
+
   InitFromStorage(async);
 }
 
 PrefService::~PrefService() {
   DCHECK(CalledOnValidThread());
 
   // Reset pointers so accesses after destruction reliably crash.
   pref_value_store_.reset();
   pref_registry_ = NULL;
   user_pref_store_ = NULL;
@@ skipping 489 matching lines @@
   return pref_value_store()->PrefValueUserModifiable(name_);
 }
 
 bool PrefService::Preference::IsExtensionModifiable() const {
   return pref_value_store()->PrefValueExtensionModifiable(name_);
 }
 
 const base::Value* PrefService::GetPreferenceValue(
     const std::string& path) const {
   DCHECK(CalledOnValidThread());
+
+  // TODO(battre): This is a check for crbug.com/435208. After analyzing some
+  // crash dumps it looks like the PrefService is accessed even though it has
+  // been cleared already.
+  CHECK(pref_registry_);
+  CHECK(pref_registry_->defaults());
+  CHECK(pref_value_store_);
+
   const base::Value* default_value = NULL;
   if (pref_registry_->defaults()->GetValue(path, &default_value)) {
     const base::Value* found_value = NULL;
     base::Value::Type default_type = default_value->GetType();
     if (pref_value_store_->GetValue(path, default_type, &found_value)) {
       DCHECK(found_value->IsType(default_type));
       return found_value;
     } else {
       // Every registered preference has at least a default value.
       NOTREACHED() << "no valid value found for registered pref " << path;
     }
   }
 
   return NULL;
 }