Remove some linked_ptr c/b/extension

chrome/browser/extensions/api/storage/managed_value_store_cache.cc

Index: chrome/browser/extensions/api/storage/managed_value_store_cache.cc
diff --git a/chrome/browser/extensions/api/storage/managed_value_store_cache.cc b/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
index 46e3228024ba118e4818ef786d492e5da18e390e..0849e1e988d02ba9ca6d77bf2290016c22a67287 100644
--- a/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
+++ b/chrome/browser/extensions/api/storage/managed_value_store_cache.cc
@@ -346,19 +346,18 @@ PolicyValueStore* ManagedValueStoreCache::GetStoreFor(
     const std::string& extension_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
 
-  PolicyValueStoreMap::iterator it = store_map_.find(extension_id);
+  auto it = store_map_.find(extension_id);
   if (it != store_map_.end())
     return it->second.get();
 
   // Create the store now, and serve the cached policy until the PolicyService
   // sends updated values.
-  PolicyValueStore* store = new PolicyValueStore(
+  store_map_[extension_id] = base::MakeUnique<PolicyValueStore>(
       extension_id, observers_,
       storage_factory_->CreateSettingsStore(settings_namespace::MANAGED,
                                             kManagedModelType, extension_id));
-  store_map_[extension_id] = make_linked_ptr(store);
 
-  return store;
+  return store_map_[extension_id].get();

[Devlin, 2016/11/02 22:25:33]

nit: we can save an extra map lookup here by doing something like:
auto store = base::MakeUnique<PolicyValueStore>(...);
PolicyValueStore* raw_store = store.get();
store_map_[extension_id] = std::move(store);
return raw_store;

[limasdf, 2016/11/03 15:29:23]

Done.

 }
 
 bool ManagedValueStoreCache::HasStore(const std::string& extension_id) const {