Do nothing in SplitWidget.showBoth if already showing

This method resulted in some unnecessary work happening in RPP, causing
the flame graph to respond to a "resize" event even though nothing
changed size. Since RPP calls this often (like when activating an
insight), this contributed to the sometimes-janky feeling caused by
opening an insight taking too long.

Bug: 40278532
Change-Id: I43b4d4e7a9b400cd3edf06f3f606e008b6455c2d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6221819
Commit-Queue: Connor Clark <[email protected]>
Reviewed-by: Paul Irish <[email protected]>

Author: Connor Clark

front_end/ui/legacy/SplitWidget.ts

@@ -398,6 +398,11 @@ export class SplitWidget extends Common.ObjectWrapper.eventMixin<EventTypes, typ
   }
 
   showBoth(animate?: boolean): void {
+    // Do nothing if both components are already showing.
+    if (!this.mainElement.classList.contains('hidden') && !this.sidebarElementInternal.classList.contains('hidden')) {
+      return;
+    }
+
     if (this.showModeInternal === ShowMode.BOTH) {
       animate = false;
     }