Fix comment in BluetoothLowEnergyAdvertisementManagerMac unit test.

Change-Id: Ic3aef8ab7e798680c0c572131f569dc93c9b4bdf
Reviewed-on: https://chromium-review.googlesource.com/1161100Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580398}

device/bluetooth/bluetooth_low_energy_advertisement_manager_mac_unittest.mm

@@ -159,7 +159,7 @@ TEST_F(BluetoothLowEnergyAdvertisementManagerMacTest,
   EXPECT_FALSE(advertisement_);
   EXPECT_FALSE(registration_error_);
 
-  // Change the adapter state to CBPeripheralManagerStateUnsupported, which
+  // Change the adapter state to CBPeripheralManagerStatePoweredOff, which
   // causes the registration to fail.
   peripheral_manager_state_ = CBPeripheralManagerStatePoweredOff;
   advertisement_manager_.OnPeripheralManagerStateChanged();