Log Matter operational advertisement removals in Matter.framework. (#37565)

Author: bzbarsky-apple

src/darwin/Framework/CHIP/MTROperationalBrowser.mm

@@ -17,6 +17,7 @@
 #import <Foundation/Foundation.h>
 
 #import "MTRDeviceControllerFactory_Internal.h"
+#import "MTRLogging_Internal.h"
 #import "MTROperationalBrowser.h"
 
 #include <cinttypes>
@@ -125,18 +126,20 @@
         return;
     }
 
-    if (!(aFlags & kDNSServiceFlagsAdd)) {
-        // We only care about new things appearing.
-        return;
-    }
-
     chip::PeerId peerId;
     CHIP_ERROR err = chip::Dnssd::ExtractIdFromInstanceName(aName, &peerId);
     if (err != CHIP_NO_ERROR) {
         ChipLogError(Controller, "Invalid instance name: '%s'\n", aName);
         return;
     }
 
+    if (!(aFlags & kDNSServiceFlagsAdd)) {
+        // We mostly only care about new things appearing, but log it when things
+        // disappear.
+        MTR_LOG("Matter operational instance advertisement removed: '%s'\n", aName);
+        return;
+    }
+
     ChipLogProgress(Controller, "Notifying controller factory about new operational instance: '%s'", aName);
     [self->mDeviceControllerFactory operationalInstanceAdded:peerId];
 }