Prepare to abstract PersistedData by making it part of the configurator.

components/update_client/update_checker.cc

Index: components/update_client/update_checker.cc
diff --git a/components/update_client/update_checker.cc b/components/update_client/update_checker.cc
index 91b07886f66ca3b8ecd4512d79ccc5b650d76011..4d70b8be75a9f81442c99eccf58f3fb9ee4fa4bb 100644
--- a/components/update_client/update_checker.cc
+++ b/components/update_client/update_checker.cc
@@ -145,8 +145,7 @@ std::string BuildUpdateCheckRequest(
 
 class UpdateCheckerImpl : public UpdateChecker {
  public:
-  UpdateCheckerImpl(const scoped_refptr<Configurator>& config,
-                    PersistedData* metadata);
+  UpdateCheckerImpl(const scoped_refptr<Configurator>& config);
   ~UpdateCheckerImpl() override;
 
   // Overrides for UpdateChecker.
@@ -176,7 +175,7 @@ class UpdateCheckerImpl : public UpdateChecker {
   base::ThreadChecker thread_checker_;
 
   const scoped_refptr<Configurator> config_;
-  PersistedData* metadata_ = nullptr;
+  std::unique_ptr<PersistedData> metadata_;
   std::vector<std::string> ids_checked_;
   UpdateCheckCallback update_check_callback_;
   std::unique_ptr<UpdaterState::Attributes> updater_state_attributes_;
@@ -185,9 +184,8 @@ class UpdateCheckerImpl : public UpdateChecker {
   DISALLOW_COPY_AND_ASSIGN(UpdateCheckerImpl);
 };
 
-UpdateCheckerImpl::UpdateCheckerImpl(const scoped_refptr<Configurator>& config,
-                                     PersistedData* metadata)
-    : config_(config), metadata_(metadata) {}
+UpdateCheckerImpl::UpdateCheckerImpl(const scoped_refptr<Configurator>& config)
+    : config_(config), metadata_(config->CreateMetadata()) {}

[waffles, 2017/05/12 17:33:34]

This will be called once per update check - I think this is OK, but it's
probably important to document that PersistedData itself can't have any state
that is supposed to live across updatechecks.

[Minh X. Nguyen, 2017/05/14 23:57:22]

As discussed offline, it's better to store PersistedData in UpdateEngine.

 
 UpdateCheckerImpl::~UpdateCheckerImpl() {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ -232,8 +230,9 @@ void UpdateCheckerImpl::CheckForUpdatesHelper(
   request_sender_ = base::MakeUnique<RequestSender>(config_);
   request_sender_->Send(
       config_->EnabledCupSigning(),
-      BuildUpdateCheckRequest(*config_, ids_checked_, components, metadata_,
-                              additional_attributes, enabled_component_updates,
+      BuildUpdateCheckRequest(*config_, ids_checked_, components,
+                              metadata_.get(), additional_attributes,
+                              enabled_component_updates,
                               updater_state_attributes_),
       urls,
       base::Bind(&UpdateCheckerImpl::OnRequestSenderComplete,
@@ -314,9 +313,8 @@ void UpdateCheckerImpl::UpdateCheckFailed(const IdToComponentPtrMap& components,
 }  // namespace
 
 std::unique_ptr<UpdateChecker> UpdateChecker::Create(
-    const scoped_refptr<Configurator>& config,
-    PersistedData* persistent) {
-  return base::MakeUnique<UpdateCheckerImpl>(config, persistent);
+    const scoped_refptr<Configurator>& config) {
+  return base::MakeUnique<UpdateCheckerImpl>(config);
 }
 
 }  // namespace update_client