Plug memory leaks in BluetoothGattChromeOSTest.*.

BUG=369379
R=armansito@chromium.org

Review URL: https://codereview.chromium.org/524693002

Cr-Commit-Position: refs/heads/master@{#292678}

chromeos/dbus/fake_bluetooth_gatt_descriptor_client.cc

@@ -56,6 +56,9 @@ FakeBluetoothGattDescriptorClient::FakeBluetoothGattDescriptorClient()
 }
 
 FakeBluetoothGattDescriptorClient::~FakeBluetoothGattDescriptorClient() {
+  for(PropertiesMap::iterator iter = properties_.begin(); iter !=
+      properties_.end(); iter++)
+    delete iter->second;
 }
 
 void FakeBluetoothGattDescriptorClient::Init(dbus::Bus* bus) {