Speculatively fix OSX crashes involving service removal

chrome/browser/local_discovery/service_discovery_client_mac.mm

Index: chrome/browser/local_discovery/service_discovery_client_mac.mm
diff --git a/chrome/browser/local_discovery/service_discovery_client_mac.mm b/chrome/browser/local_discovery/service_discovery_client_mac.mm
index 6e91e6285b141c6555bfdda0aa0a915d0705ac04..9ad75b4db07eb9ecb5603a869a9210066e517409 100644
--- a/chrome/browser/local_discovery/service_discovery_client_mac.mm
+++ b/chrome/browser/local_discovery/service_discovery_client_mac.mm
@@ -431,11 +431,12 @@ ServiceResolverImplMac::GetContainerForTesting() {
 - (void)netServiceBrowser:(NSNetServiceBrowser *)netServiceBrowser
         didRemoveService:(NSNetService *)netService
         moreComing:(BOOL)moreServicesComing {
-  container_->OnServicesUpdate(local_discovery::ServiceWatcher::UPDATE_REMOVED,
-                               [[netService name] UTF8String]);
-
   NSUInteger index = [services_ indexOfObject:netService];
   if (index != NSNotFound) {
+    container_->OnServicesUpdate(
+        local_discovery::ServiceWatcher::UPDATE_REMOVED,
+        [[netService name] UTF8String]);
+
     // Stop monitoring this service for updates.
     [[services_ objectAtIndex:index] stopMonitoring];
     [services_ removeObjectAtIndex:index];