MSE, MS, and any blob URL: Ignore preload 'none' on resource fetching

Prevents the usage of the optional resource fetch algorithm steps for
when preload='none' in the MSE, MediaStream source, or any blob URL
cases.  Complies with recent update to MSE spec [1] and fixes the
related crbug.com/539707. Includes test coverage for MSE and invalid
(revoked MSE object) blob URLs. MediaStream test coverage is expected to
come from later import of a new web-platform-tests [2].

[1] https://github.com/w3c/media-source/pull/64
[2] https://github.com/w3c/web-platform-tests/pull/2895

R=philipj@opera.com
TBR=srirama.m@samsung.com
BUG=539707
TEST=http/tests/media/media-source/mediasource-preload.html

Review URL: https://codereview.chromium.org/1881733004

Cr-Commit-Position: refs/heads/master@{#389649}
2 files changed