Zero is a valid advertiser id

Test: start advertising using bluetooth-cli
Change-Id: Iead31c5e73a70850c6a209b6bbbeaeb792202608
diff --git a/service/client/main.cc b/service/client/main.cc
index be3409c..be6b15e 100644
--- a/service/client/main.cc
+++ b/service/client/main.cc
@@ -96,8 +96,9 @@
 
 // The registered IBluetoothLeAdvertiser handle. If |ble_advertiser_registering|
 // is true then an operation to register the advertiser is in progress.
+const int invalid_advertiser_id = -1;
 std::atomic_bool ble_advertiser_registering(false);
-std::atomic_int ble_advertiser_id(0);
+std::atomic_int ble_advertiser_id(invalid_advertiser_id);
 
 // The registered IBluetoothLeScanner handle. If |ble_scanner_registering| is
 // true then an operation to register the scanner is in progress.
@@ -440,7 +441,7 @@
     return;
   }
 
-  if (ble_advertiser_id.load()) {
+  if (ble_advertiser_id.load() != invalid_advertiser_id) {
     PrintError("Already registered");
     return;
   }
@@ -463,7 +464,7 @@
                                    const vector<string>& args) {
   CHECK_NO_ARGS(args);
 
-  if (!ble_advertiser_id.load()) {
+  if (ble_advertiser_id.load() == invalid_advertiser_id) {
     PrintError("Not registered");
     return;
   }
@@ -476,7 +477,7 @@
   }
 
   ble_advertiser_iface->UnregisterAdvertiser(ble_advertiser_id.load());
-  ble_advertiser_id = 0;
+  ble_advertiser_id = invalid_advertiser_id;
   PrintCommandStatus(true);
 }
 
@@ -638,7 +639,7 @@
     }
   }
 
-  if (!ble_advertiser_id.load()) {
+  if (ble_advertiser_id.load() == invalid_advertiser_id) {
     PrintError("BLE advertiser not registered");
     return;
   }
@@ -710,7 +711,7 @@
 }
 
 void HandleStopAdv(IBluetooth* bt_iface, const vector<string>& args) {
-  if (!ble_advertiser_id.load()) {
+  if (ble_advertiser_id.load() == invalid_advertiser_id) {
     PrintError("BLE advertiser not registered");
     return;
   }
diff --git a/service/ipc/binder/interface_with_instances_base.cc b/service/ipc/binder/interface_with_instances_base.cc
index 2005bf0..18b1eae 100644
--- a/service/ipc/binder/interface_with_instances_base.cc
+++ b/service/ipc/binder/interface_with_instances_base.cc
@@ -124,7 +124,6 @@
 
   std::lock_guard<std::mutex> lock(maps_lock_);
   int instance_id = instance->GetInstanceId();
-  CHECK(instance_id);
   if (!id_to_cb_.Register(instance_id, callback, this)) {
     LOG(ERROR) << "Failed to store callback";
     OnRegisterInstanceImpl(bluetooth::BLE_STATUS_FAILURE, callback, nullptr);