When Cache API is not available, dont clone response for cachePut

[asheemmamoowala]

The cacheGet method calls back to validateOrFetch with a null error if window.caches is not available. From what I can tell, this could happen when the Cache API is not available at all or if a page is served over http and the Cache API is not usable.

mapbox-gl-js/src/util/tile_request_cache.js

Lines 72 to 81 in dd5dcd0

	export function cacheGet(request: Request, callback: (error: ?any, response: ?Response, fresh: ?boolean) => void) {
	if (!window.caches) return callback(null);
	window.caches.open(CACHE_NAME)
	.catch(callback)
	.then(cache => {
	cache.match(request, { ignoreSearch: true })
	.catch(callback)
	.then(response => {

In this case validateOrFetch still calls clones the response and attempts to place it in the cache.

mapbox-gl-js/src/util/ajax.js

Lines 127 to 131 in dd5dcd0

	window.fetch(request).then(response => {
	if (response.ok) {
	const cacheableResponse = cacheIgnoringSearch ? response.clone() : null;
	return finishRequest(response, cacheableResponse, requestTime);

If it is known that window.caches is no available or usable, there is not need to clone the response or to load its contents:

mapbox-gl-js/src/util/ajax.js

Lines 144 to 152 in dd5dcd0

	const finishRequest = (response, cacheableResponse, requestTime) => {
	(
	requestParameters.type === 'arrayBuffer' ? response.arrayBuffer() :
	requestParameters.type === 'json' ? response.json() :
	response.text()
	).then(result => {
	if (cacheableResponse && requestTime) {
	// The response needs to be inserted into the cache after it has completely loaded.

[ahk]

Didn't a fix for this get merged into our most recent release as a late patch, or do I misunderstand the extent of the bug?

[asheemmamoowala]

@ahk This was not addressed. I can still reproduce this in the latest master.