Fix memory trend for Node.js targets

The new memory usage fields are available after V8 13.4. Node.js
has not yet been released with this version of V8 yet.

Bug: 40734351
Change-Id: Ie3b9777e6983ff26ee625e78ea385158b80252a5
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6317029
Reviewed-by: Simon Zünd <[email protected]>
Reviewed-by: Philip Pfaffe <[email protected]>
Commit-Queue: Simon Zünd <[email protected]>

Author: legendecas

front_end/core/sdk/IsolateManager.ts

@@ -178,7 +178,7 @@ export class Isolate {
     if (!usage) {
       return;
     }
-    this.#usedHeapSizeInternal = usage.usedSize + usage.embedderHeapUsedSize + usage.backingStorageSize;
+    this.#usedHeapSizeInternal = usage.usedSize + (usage.embedderHeapUsedSize ?? 0) + (usage.backingStorageSize ?? 0);
     this.#memoryTrend.add(this.#usedHeapSizeInternal);
     IsolateManager.instance().dispatchEventToListeners(Events.MEMORY_CHANGED, this);
   }

front_end/core/sdk/RuntimeModel.ts

@@ -269,8 +269,9 @@ export class RuntimeModel extends SDKModel<EventTypes> {
   async heapUsage(): Promise<{
     usedSize: number,
     totalSize: number,
-    embedderHeapUsedSize: number,
-    backingStorageSize: number,
+    // Available after V8 13.4. Node.js has not yet been released with this version of V8 yet.
+    embedderHeapUsedSize?: number,
+    backingStorageSize?: number,
   }|null> {
     const result = await this.agent.invoke_getHeapUsage();
     return result.getError() ? null : result;