arc: bluetooth: Check invalid handle in DeleteService

Since |service_handle| from Android might be invalid, we need an early
return instead of DCHECK().

BUG=b:147707738
TEST=When Fitbit is installed, no crash in cts test now.

Change-Id: Ia9aa8402960bb40457bd81a3d09b26a41aa27601
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2000401Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Jie Jiang <jiejiang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732684}

chrome/browser/chromeos/arc/bluetooth/arc_bluetooth_bridge.cc

@@ -1918,11 +1918,16 @@ void ArcBluetoothBridge::StopService(int32_t service_handle,
 void ArcBluetoothBridge::DeleteService(int32_t service_handle,
                                        DeleteServiceCallback callback) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
-  DCHECK(gatt_identifier_.find(service_handle) != gatt_identifier_.end());
+  auto itr = gatt_identifier_.find(service_handle);
+  if (itr == gatt_identifier_.end()) {
+    LOG(WARNING) << "DeleteService called with invalid service handle.";
+    return;
+  }
+
   BluetoothLocalGattService* service =
-      bluetooth_adapter_->GetGattService(gatt_identifier_[service_handle]);
+      bluetooth_adapter_->GetGattService(itr->second);
   DCHECK(service);
-  gatt_identifier_.erase(service_handle);
+  gatt_identifier_.erase(itr);
   gatt_handle_.erase(service->GetIdentifier());
   service->Delete();
   OnGattOperationDone(std::move(callback));