[system-analyzer] Fix zoom

Don't render if the timeline track doesn't have any data.

Change-Id: Ib0638ce18391f14212d3a5385d90877cf0392c5f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3162042Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76843}

tools/system-analyzer/view/timeline/timeline-track-base.mjs

@@ -170,6 +170,9 @@ export class TimelineTrackBase extends V8CustomElement {
   }
 
   _updateDimensions() {
+    // No data in this timeline, no need to resize
+    if (!this._timeline) return;
+
     const centerOffset = this._timelineBoundingClientRect.width / 2;
     const time =
         this.relativePositionToTime(this._timelineScrollLeft + centerOffset);