Fix background plugin stats

Summary: Discovered that all gathered plugin stats where empty due to mis-using Object.entries. Fixed that. Also added a accumulated cpuTime metric, which should be great for a uniform trend line.

Reviewed By: jknoxville

Differential Revision: D19517279

fbshipit-source-id: a6df83eea000a5d59fe692a3795fd58ae6457821

src/utils/messageQueue.tsx

@@ -38,14 +38,23 @@ export function resetPluginBackgroundStatsDelta() {
   });
 }
 
-export function getPluginBackgroundStats(): {[plugin: string]: StatEntry} {
-  return Array.from(Object.entries(pluginBackgroundStats)).reduce(
+export function getPluginBackgroundStats(): {
+  cpuTime: number; // amount of ms cpu used since the last stats (typically every minute)
+  byPlugin: {[plugin: string]: StatEntry};
+} {
+  let cpuTime: number = 0;
+  const byPlugin = Array.from(pluginBackgroundStats.entries()).reduce(
     (aggregated, [pluginName, data]) => {
+      cpuTime += data.cpuTimeDelta;
       aggregated[pluginName] = data;
       return aggregated;
     },
     {} as {[plugin: string]: StatEntry},
   );
+  return {
+    cpuTime,
+    byPlugin,
+  };
 }
 
 if (window) {