Renderer cache error handling

[rochoa]

Windshaft/lib/windshaft/cache/renderer_cache.js

Lines 82 to 86 in 649f579

	cacheEntry.on('error', function(err) {
	debug("Removing RendererCache " + key + " on error " + err);
	self.emit('err', err);
	self.del(key);
	});

Any error on a renderer drops the renderer from the cache. As a general approach it feels really good, as you start with a clean slate, however, recreating the renderer might be an expensive operation.

There are two potential alternatives here:

• Allow to set what kind of errors should drop/recreate the renderer.
• Improve renderer creation and keep this piece as it is: let it crash style.