Add missing callback from SessionStorageNamespaceImplMojo::RemoveOriginData

SessionStorageNamespaceImplMojo::RemoveOriginData didn't call its
callback when the origin was not found in origin_areas_.


Bug: 963533
Change-Id: Id71bc617d0d9d28d164a1f0ec97e76d18c2b1b47
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615180Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661300}

content/browser/dom_storage/session_storage_namespace_impl_mojo.cc

@@ -131,8 +131,10 @@ void SessionStorageNamespaceImplMojo::RemoveOriginData(
   }
   DCHECK(IsPopulated());
   auto it = origin_areas_.find(origin);
-  if (it == origin_areas_.end())
+  if (it == origin_areas_.end()) {
+    std::move(callback).Run();
     return;
+  }
   // Renderer process expects |source| to always be two newline separated
   // strings.
   it->second->DeleteAll(