Add karma_closure to package.json.
Add karma_closure to package.json.

dq922/PerfKitExplorer,dq922/PerfKitExplorer,GoogleCloudPlatform/PerfKitExplorer,GoogleCloudPlatform/PerfKitExplorer,GoogleCloudPlatform/PerfKitExplorer,GoogleCloudPlatform/PerfKitExplorer,dq922/PerfKitExplorer,dq922/PerfKitExplorer