"Code - Helper (GPU)" process uses 20+% CPU when a spinner is shown in status bar

[evangrayk]

• VSCode Version: 1.44 insiders
• OS Version: macOS 10.15.3

Steps to Reproduce:

1. Have an extension that creates a status bar with a spinner, e.g.:

const vscode = require('vscode');
export function activate(context) {
    const statusBar = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Left);
    statusBar.text = '$(sync~spin) Test';
    statusBar.show();
    context.subscriptions.push(statusBar);
}

(Often times extensions show status bar spinners for long running background tasks)

2. When this spinner is shown, use Activity Monitor on macOS to view CPU usage. The "Code - GPU" process will use more CPU than desired just to show the spinner. On a completely blank build of VSCode, this is 5-10%. In a more typical example with extensions installed and files open, this as much as 25% CPU usage (typically 20% for me in everyday scenarios).
3. To verify it's the spinner causing this, either: 1) hide status bar via right click and watch CPU usage go down to 1% or 2) use dev tools to disable animation CSS property and see CPU usage drop.

FWIW, this also happens to some extent in Chrome itself (the "Chrome - GPU" process) if you show a CSS animation there. Animated GIFs or less frequent animations perform better in web.

Does this issue occur when all extensions are disabled?: No, because you need a spinner to be shown. Should also repro for file tree loading spinner, but that is less long-lived.

[joaomoreno]

Verification: code review #96096