[Nearby] Extend local-device-data sync period from 1 hour to 12 hours

The contact and certificate download period is 12 hours. Change the
download period of full name and icon URL from 1 hour to 12 hours.
There was no good reason why this was 1 hour. In a separate CL, all
relevant data will also be downloaded from the Nearby server when
Nearby Share is actively in use to ensure freshness.

Change-Id: I3772f5c8f88d0129a5d41367fd1222197a0ca938
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505590
Auto-Submit: Josh Nohle <nohle@chromium.org>
Commit-Queue: James Vecore <vecore@google.com>
Reviewed-by: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#821747}

chrome/browser/nearby_sharing/local_device_data/nearby_share_local_device_data_manager_impl.cc

@@ -36,7 +36,7 @@ constexpr std::array<char, 36> kAlphaNumericChars = {
 constexpr base::TimeDelta kUpdateDeviceDataTimeout =
     base::TimeDelta::FromSeconds(30);
 constexpr base::TimeDelta kDeviceDataDownloadPeriod =
-    base::TimeDelta::FromHours(1);
+    base::TimeDelta::FromHours(12);
 
 }  // namespace
 

chrome/browser/nearby_sharing/local_device_data/nearby_share_local_device_data_manager_impl_unittest.cc

@@ -227,7 +227,7 @@ class NearbyShareLocalDeviceDataManagerImplTest
             scheduler_factory_.pref_name_to_periodic_instance().at(
                 prefs::kNearbySharingSchedulerDownloadDeviceDataPrefName);
     EXPECT_TRUE(device_data_scheduler_instance.fake_scheduler);
-    EXPECT_EQ(base::TimeDelta::FromHours(1),
+    EXPECT_EQ(base::TimeDelta::FromHours(12),
               device_data_scheduler_instance.request_period);
     EXPECT_TRUE(device_data_scheduler_instance.retry_failures);
     EXPECT_TRUE(device_data_scheduler_instance.require_connectivity);