[CrOS PhoneHub] Fix issue which causes crash on Linux build

This CL changes FeatureStatusProviderImpl logic to check whether
DeviceSyncClient is ready before continuing. In real-world usage, this
will always be the case, but on the Linux emulator this condition is not
true, causing a crash.

Bug: 1106937
Change-Id: Ie99d4085697867b730b81e52f28b0afdbb7a46f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2405901
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Auto-Submit: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806318}

chromeos/components/phonehub/feature_status_provider_impl.cc

@@ -205,7 +205,11 @@ FeatureStatus FeatureStatusProviderImpl::ComputeStatus() {
   FeatureState feature_state =
       multidevice_setup_client_->GetFeatureState(Feature::kPhoneHub);
 
-  if (!IsEligibleForFeature(device_sync_client_->GetLocalDeviceMetadata(),
+  // Note: If |device_sync_client_| is not yet ready, it has not initialized
+  // itself with device metadata, so we assume that we are ineligible for the
+  // feature until proven otherwise.
+  if (!device_sync_client_->is_ready() ||
+      !IsEligibleForFeature(device_sync_client_->GetLocalDeviceMetadata(),
                             device_sync_client_->GetSyncedDevices(),
                             feature_state)) {
     return FeatureStatus::kNotEligibleForFeature;

chromeos/components/phonehub/feature_status_provider_impl_unittest.cc

@@ -100,6 +100,7 @@ class FeatureStatusProviderImplTest : public testing::Test {
         .WillByDefault(
             Invoke(this, &FeatureStatusProviderImplTest::is_adapter_powered));
     device::BluetoothAdapterFactory::SetAdapterForTesting(mock_adapter_);
+    fake_device_sync_client_.NotifyReady();
 
     provider_ = std::make_unique<FeatureStatusProviderImpl>(
         &fake_device_sync_client_, &fake_multidevice_setup_client_,