Fix duplicate devices when multiple mediums scanning requested

The dedupuing logic was already in place, but there was a race
due to managin the list of devices from different threads.

Test: using wear app ensure dup device reproduses without CL, and not with it
Fixes: 160870456
Change-Id: I1526199e8e4fb4b8f7d7f306e9e676359cdca516

core/java/android/companion/BluetoothDeviceFilter.java

@@ -141,6 +141,16 @@ public final class BluetoothDeviceFilter implements DeviceFilter<BluetoothDevice
         return Objects.hash(mNamePattern, mAddress, mServiceUuids, mServiceUuidMasks);
     }
 
+    @Override
+    public String toString() {
+        return "BluetoothDeviceFilter{"
+                + "mNamePattern=" + mNamePattern
+                + ", mAddress='" + mAddress + '\''
+                + ", mServiceUuids=" + mServiceUuids
+                + ", mServiceUuidMasks=" + mServiceUuidMasks
+                + '}';
+    }
+
     @Override
     public int describeContents() {
         return 0;

packages/CompanionDeviceManager/src/com/android/companiondevicemanager/DeviceDiscoveryService.java

@@ -259,18 +259,19 @@ public class DeviceDiscoveryService extends Service {
     private void onDeviceFound(@Nullable DeviceFilterPair device) {
         if (device == null) return;
 
-        if (mDevicesFound.contains(device)) {
-            return;
-        }
-
-        if (DEBUG) Log.i(LOG_TAG, "Found device " + device);
-
         Handler.getMain().sendMessage(obtainMessage(
                 DeviceDiscoveryService::onDeviceFoundMainThread, this, device));
     }
 
     @MainThread
     void onDeviceFoundMainThread(@NonNull DeviceFilterPair device) {
+        if (mDevicesFound.contains(device)) {
+            Log.i(LOG_TAG, "Skipping device " + device + " - already among found devices");
+            return;
+        }
+
+        Log.i(LOG_TAG, "Found device " + device);
+
         if (mDevicesFound.isEmpty()) {
             onReadyToShowUI();
         }
@@ -432,10 +433,10 @@ public class DeviceDiscoveryService extends Service {
 
         @Override
         public String toString() {
-            return "DeviceFilterPair{" +
-                    "device=" + device +
-                    ", filter=" + filter +
-                    '}';
+            return "DeviceFilterPair{"
+                    + "device=" + device + " " + getDisplayName()
+                    + ", filter=" + filter
+                    + '}';
         }
     }