[Offline Pages] Handle prerender FinalStatus UnsupportedScheme as a cancel rather than failure. Los…

[Offline Pages] Handle prerender FinalStatus UnsupportedScheme as a cancel rather than failure. Losing network connection while prerendering can show up as an Unsupported Scheme failure currently as it sees a special data URL in path toward rendering an error page. We don't want a flakey network connection fail a background load request on just a single try, so for now, we will treat this specific error type as a cancel rather than a failure so that it is subject some limited retrying. The down side, is that for some page that has a repeatable redirect to an unsupported scheme, we will waste some retries on it that we otherwise could skip.

Ideally, we could get a different final status code from the prerenderer if it could clearly distinguish a network failure condition but it does not currently have such knowledge.

BUG=642025
Review-Url: https://codereview.chromium.org/2294933003
Cr-Commit-Position: refs/heads/master@{#415673}
(cherry picked from commit 27e86c877f293dec2693281e7848e4d61a95ba4c)

Committed: https://chromium.googlesource.com/chromium/src/+/fb7fb8344b2af613675770e6446e21d847fcaefb

[Pete Williamson, 2016-08-31 21:41:56]

Description was changed from

==========
[Offline Pages] Handle prerender FinalStatus UnsupportedScheme as a cancel
rather than failure. Losing network connection while prerendering can show up as
an Unsupported Scheme failure currently as it sees a special data URL in path
toward rendering an error page. We don't want a flakey network connection fail a
background load request on just a single try, so for now, we will treat this
specific error type as a cancel rather than a failure so that it is subject some
limited retrying. The down side, is that for some page that has a repeatable
redirect to an unsupported scheme, we will waste some retries on it that we
otherwise could skip.

Ideally, we could get a different final status code from the prerenderer if it
could clearly distinguish a network failure condition but it does not currently
have such knowledge.

BUG=642025

Review-Url: https://codereview.chromium.org/2294933003
Cr-Commit-Position: refs/heads/master@{#415673}
(cherry picked from commit 27e86c877f293dec2693281e7848e4d61a95ba4c)
==========

to

==========
[Offline Pages] Handle prerender FinalStatus UnsupportedScheme as a cancel
rather than failure. Losing network connection while prerendering can show up as
an Unsupported Scheme failure currently as it sees a special data URL in path
toward rendering an error page. We don't want a flakey network connection fail a
background load request on just a single try, so for now, we will treat this
specific error type as a cancel rather than a failure so that it is subject some
limited retrying. The down side, is that for some page that has a repeatable
redirect to an unsupported scheme, we will waste some retries on it that we
otherwise could skip.

Ideally, we could get a different final status code from the prerenderer if it
could clearly distinguish a network failure condition but it does not currently
have such knowledge.

BUG=642025

Review-Url: https://codereview.chromium.org/2294933003
Cr-Commit-Position: refs/heads/master@{#415673}
(cherry picked from commit 27e86c877f293dec2693281e7848e4d61a95ba4c)

Committed:
https://chromium.googlesource.com/chromium/src/+/fb7fb8344b2af613675770e6446e...
==========

[Pete Williamson, 2016-08-31 21:41:57]

Committed patchset #1 (id:1) manually as
fb7fb8344b2af613675770e6446e21d847fcaefb.