crash: Fixes following r413431

components/crash/content/browser/crash_dump_observer_android.cc

Index: components/crash/content/browser/crash_dump_observer_android.cc
diff --git a/components/crash/content/browser/crash_dump_observer_android.cc b/components/crash/content/browser/crash_dump_observer_android.cc
index a7acdd89e51be855804d61aeb8f18473adb31c34..6a159f95335924cc4f0a28c806c038a14f775ba1 100644
--- a/components/crash/content/browser/crash_dump_observer_android.cc
+++ b/components/crash/content/browser/crash_dump_observer_android.cc
@@ -32,9 +32,12 @@ CrashDumpObserver::CrashDumpObserver() {
   notification_registrar_.Add(this,
                               content::NOTIFICATION_RENDERER_PROCESS_CLOSED,
                               content::NotificationService::AllSources());
+  BrowserChildProcessObserver::Add(this);
 }
 
-CrashDumpObserver::~CrashDumpObserver() {}
+CrashDumpObserver::~CrashDumpObserver() {
+  BrowserChildProcessObserver::Remove(this);
+}
 
 void CrashDumpObserver::OnChildExitOnBlockingPool(
     Client* client,