[Nearby] Fix default device name format.

In certain cases the default device name can be generated without the
user's given name, e.g. just "Chromebook". This occurs when adding a
second user account to a device, where the default device name is
generated immediately on completing login but before user details have
been downloaded.

This updated logic caches the default device name in the
NearbyShareLocalDeviceDataManagerImpl rather than storing it in prefs.

Fixed: 1151667
Change-Id: Ica79907506624647f630a798f08d9201ea381a6d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2622592Reviewed-by: Josh Nohle <nohle@chromium.org>
Commit-Queue: Michael Hansen <hansenmichael@google.com>
Cr-Commit-Position: refs/heads/master@{#842087}

chrome/browser/nearby_sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc

@@ -85,10 +85,9 @@ NearbyShareLocalDeviceDataManagerImpl::NearbyShareLocalDeviceDataManagerImpl(
               pref_service_,
               base::BindRepeating(&NearbyShareLocalDeviceDataManagerImpl::
                                       OnDownloadDeviceDataRequested,
-                                  base::Unretained(this)))) {
-  DCHECK(!default_device_name.empty());
-  if (GetDeviceName().empty())
-    SetDeviceName(default_device_name);
+                                  base::Unretained(this)))),
+      default_device_name_(default_device_name) {
+  DCHECK(!default_device_name_.empty());
 }
 
 NearbyShareLocalDeviceDataManagerImpl::
@@ -109,7 +108,9 @@ std::string NearbyShareLocalDeviceDataManagerImpl::GetId() {
 }
 
 std::string NearbyShareLocalDeviceDataManagerImpl::GetDeviceName() const {
-  return pref_service_->GetString(prefs::kNearbySharingDeviceNamePrefName);
+  std::string device_name =
+      pref_service_->GetString(prefs::kNearbySharingDeviceNamePrefName);
+  return device_name.empty() ? default_device_name_ : device_name;
 }
 
 base::Optional<std::string> NearbyShareLocalDeviceDataManagerImpl::GetFullName()

chrome/browser/nearby_sharing/local_device_data/nearby_share_local_device_data_manager_impl.h

@@ -89,6 +89,7 @@ class NearbyShareLocalDeviceDataManagerImpl
   PrefService* pref_service_ = nullptr;
   std::unique_ptr<NearbyShareDeviceDataUpdater> device_data_updater_;
   std::unique_ptr<NearbyShareScheduler> download_device_data_scheduler_;
+  std::string default_device_name_;
 };
 
 #endif  // CHROME_BROWSER_NEARBY_SHARING_LOCAL_DEVICE_DATA_NEARBY_SHARE_LOCAL_DEVICE_DATA_MANAGER_IMPL_H_