Allow retrieval of media device ID salt even after ResourceContext has gone away.

chrome/browser/profiles/profile_io_data.cc

Index: chrome/browser/profiles/profile_io_data.cc
diff --git a/chrome/browser/profiles/profile_io_data.cc b/chrome/browser/profiles/profile_io_data.cc
index d6350eca92a8202446bfb8394f2a1e72e932a740..0c7f5aa3fcadc1c9d3c99a17cc40271c82e45e82 100644
--- a/chrome/browser/profiles/profile_io_data.cc
+++ b/chrome/browser/profiles/profile_io_data.cc
@@ -419,8 +419,7 @@ void ProfileIOData::InitializeOnUIThread(Profile* profile) {
                             local_state_pref_service);
   quick_check_enabled_.MoveToThread(io_message_loop_proxy);
 
-  media_device_id_salt_.reset(new MediaDeviceIDSalt(pref_service,
-                                                    is_incognito()));
+  media_device_id_salt_ = new MediaDeviceIDSalt(pref_service, is_incognito());
 
   network_prediction_enabled_.Init(prefs::kNetworkPredictionEnabled,
                                    pref_service);
@@ -730,8 +729,8 @@ HostContentSettingsMap* ProfileIOData::GetHostContentSettingsMap() const {
   return host_content_settings_map_.get();
 }
 
-std::string ProfileIOData::GetMediaDeviceIDSalt() const {
-  return media_device_id_salt_->GetSalt();
+ResourceContext::SaltCallback ProfileIOData::GetMediaDeviceIDSalt() const {
+  return base::Bind(&MediaDeviceIDSalt::GetSalt, media_device_id_salt_);
 }
 
 void ProfileIOData::InitializeMetricsEnabledStateOnUIThread() {
@@ -876,7 +875,8 @@ bool ProfileIOData::ResourceContext::AllowContentAccess(
   return setting == CONTENT_SETTING_ALLOW;
 }
 
-std::string ProfileIOData::ResourceContext::GetMediaDeviceIDSalt() {
+ResourceContext::SaltCallback
+ProfileIOData::ResourceContext::GetMediaDeviceIDSalt() {
   return io_data_->GetMediaDeviceIDSalt();
 }