DCHECK(CalledOnValidThread()) for ScopedUserPrefUpdate

BUG=392781

Review URL: https://codereview.chromium.org/383683002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282362 0039d316-1c4b-4281-b951-d872f2087c98

base/prefs/pref_service.cc

@@ -432,6 +432,7 @@ base::Value* PrefService::GetMutableUserPref(const char* path,
 }
 
 void PrefService::ReportUserPrefChanged(const std::string& key) {
+  DCHECK(CalledOnValidThread());
   user_pref_store_->ReportValueChanged(key);
 }
 

base/prefs/scoped_user_pref_update.cc

@@ -14,13 +14,16 @@ ScopedUserPrefUpdateBase::ScopedUserPrefUpdateBase(PrefService* service,
                                                    const char* path)
     : service_(service),
       path_(path),
-      value_(NULL) {}
+      value_(NULL) {
+  DCHECK(service_->CalledOnValidThread());
+}
 
 ScopedUserPrefUpdateBase::~ScopedUserPrefUpdateBase() {
   Notify();
 }
 
 base::Value* ScopedUserPrefUpdateBase::GetValueOfType(base::Value::Type type) {
+  DCHECK(CalledOnValidThread());
   if (!value_)
     value_ = service_->GetMutableUserPref(path_.c_str(), type);
   return value_;