[fido] Fix FIDO BLE tests which use BluetoothTest

These tests use BluetoothTest to create a platform-specific fake
adapter. Since FidoBleDiscovery uses BluetoothAdapterFactory to get the
BluetoothAdapter SetAdapterForTesting() must be called to register this
fake adapter with the factory so that the tests use the right one.

Bug: 1071677
Change-Id: I3cc53f39bbd492a0901e334cea0308c65fde4b8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2153938Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Auto-Submit: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759886}

device/fido/ble/fido_ble_discovery_unittest.cc

@@ -186,6 +186,7 @@ TEST_F(BluetoothTest, FidoBleDiscoveryFindsKnownDevice) {
     return;
   }
   InitWithFakeAdapter();
+  BluetoothAdapterFactory::SetAdapterForTesting(adapter_);
 
   SimulateLowEnergyDevice(4);  // This device should be ignored.
   SimulateLowEnergyDevice(7);
@@ -215,6 +216,7 @@ TEST_F(BluetoothTest, FidoBleDiscoveryFindsNewDevice) {
     return;
   }
   InitWithFakeAdapter();
+  BluetoothAdapterFactory::SetAdapterForTesting(adapter_);
 
   FidoBleDiscovery discovery;
   MockFidoDiscoveryObserver observer;
@@ -258,6 +260,7 @@ TEST_F(BluetoothTest, FidoBleDiscoveryFindsUpdatedDevice) {
     return;
   }
   InitWithFakeAdapter();
+  BluetoothAdapterFactory::SetAdapterForTesting(adapter_);
 
   SimulateLowEnergyDevice(3);
 
@@ -306,6 +309,7 @@ TEST_F(BluetoothTest, FidoBleDiscoveryRejectsCableDevice) {
     return;
   }
   InitWithFakeAdapter();
+  BluetoothAdapterFactory::SetAdapterForTesting(adapter_);
 
   FidoBleDiscovery discovery;
   MockFidoDiscoveryObserver observer;