Consolidate stats tracker consts, and add Usage to tracker test

ui/app/utils/classes/allocation-stats-tracker.js

@@ -49,12 +49,10 @@ class AllocationStatsTracker extends EmberObject.extend(AbstractStatsTracker) {
       percent: percent(cpuUsed, this.reservedCPU),
     });
 
-    let memoryUsed = 0;
-    if (frame.ResourceUsage.MemoryStats.Usage) {
-      memoryUsed = frame.ResourceUsage.MemoryStats.Usage;
-    } else {
-      memoryUsed = frame.ResourceUsage.MemoryStats.RSS;
-    }
+    const memoryUsed =
+      frame.ResourceUsage.MemoryStats.Usage ||
+      frame.ResourceUsage.MemoryStats.RSS ||
+      0;
 
     this.memory.pushObject({
       timestamp,
@@ -86,12 +84,10 @@ class AllocationStatsTracker extends EmberObject.extend(AbstractStatsTracker) {
         percentStack: percentCpuTotal + aggregateCpu,
       });
 
-      let taskMemoryUsed = 0;
-      if (frame.ResourceUsage.MemoryStats.Usage) {
-        taskMemoryUsed = frame.ResourceUsage.MemoryStats.Usage;
-      } else {
-        taskMemoryUsed = frame.ResourceUsage.MemoryStats.RSS;
-      }
+      const taskMemoryUsed =
+        frame.ResourceUsage.MemoryStats.Usage ||
+        frame.ResourceUsage.MemoryStats.RSS ||
+        0;
 
       const percentMemoryTotal = percent(
         taskMemoryUsed / 1024 / 1024,

ui/tests/unit/utils/allocation-stats-tracker-test.js

@@ -54,6 +54,7 @@ module('Unit | Util | AllocationStatsTracker', function () {
       },
       MemoryStats: {
         RSS: (step + 400) * 1024 * 1024,
+        Usage: (step + 400) * 1024 * 1024,
       },
     },
     Tasks: {
@@ -64,6 +65,7 @@ module('Unit | Util | AllocationStatsTracker', function () {
           },
           MemoryStats: {
             RSS: (step + 100) * 1024 * 1024,
+            Usage: (step + 100) * 1024 * 1024,
           },
         },
         Timestamp: refDate + step,
@@ -75,6 +77,7 @@ module('Unit | Util | AllocationStatsTracker', function () {
           },
           MemoryStats: {
             RSS: (step + 50) * 1024 * 1024,
+            Usage: (step + 50) * 1024 * 1024,
           },
         },
         Timestamp: refDate + step * 10,
@@ -86,6 +89,7 @@ module('Unit | Util | AllocationStatsTracker', function () {
           },
           MemoryStats: {
             RSS: (step + 51) * 1024 * 1024,
+            Usage: (step + 51) * 1024 * 1024,
           },
         },
         Timestamp: refDate + step * 100,