Fetch API: Add Request#cache attribute
Behind the run time flag FetchRequestCache, a new attribute |cache|
is added into fetch request. Cache can be set to "default", "no-store",
"reload", "no-cache", "force-cache" or "only-if-cached". Please refer
to https://fetch.spec.whatwg.org/#requestsNote for exact definition.
Note that the implementation of cache options are not completed yet.
TEST=request-init-003.sub.html
BUG=453190
Review-Url: https://codereview.chromium.org/2811623002
Cr-Commit-Position: refs/heads/master@{#464032}
21 files changed
