[meta] Loading animation broken in Firefox 32+

[Infocatcher]

Affected:

• Check for Addons Updates
• Extensions Developer Tools
• Extensions Installer

We use chrome://browser/skin/tabbrowser/connecting.png chrome://browser/skin/tabbrowser/loading.png that aren't animated anymore, see chrome://browser/skin/browser.css

@keyframes throbber-loading {
  to {
    transform: rotate(360deg);
  }
}

@keyframes throbber-connecting {
  from {
    transform: rotate(360deg);
  }
}

.tab-throbber[busy] {
  list-style-image: url("chrome://browser/skin/tabbrowser/connecting.png");
  animation-duration: 960ms;
  animation-iteration-count: infinite;
  animation-name: throbber-connecting;
  animation-timing-function: linear;
}

.tab-throbber[progress] {
  list-style-image: url("chrome://browser/skin/tabbrowser/loading.png");
  animation-duration: 800ms;
  animation-name: throbber-loading;
}

Or we can use alternative: chrome://global/skin/icons/loading_16.png