Add a version of WebApplicationCacheHost::willStartMainResourceRequest that doesn't depend on WebFr…

Add a version of WebApplicationCacheHost::willStartMainResourceRequest that doesn't depend on WebFrame

This is in preparation for removing WebApplicationCacheHost's dependency
public/web, allowing it to move to public/platform (and thus allow it to
be referenced from core).

BUG=343272
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=167055

[adamk, 2014-02-12 22:19:16]

See https://codereview.chromium.org/161573002/ for how the Chromium side will
make use of this patch.

[abarth-chromium, 2014-02-12 22:20:05]

lgtm

[michaeln, 2014-02-12 22:24:50]

lgtm2

[adamk, 2014-02-12 22:27:50]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2014-02-12 22:28:02]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/adamk@chromium.org/161303003/1

[commit-bot: I haz the power, 2014-02-12 22:37:44]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/adamk@chromium.org/161303003/1

[commit-bot: I haz the power, 2014-02-12 22:38:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/adamk@chromium.org/161303003/1

[commit-bot: I haz the power, 2014-02-12 22:44:26]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/adamk@chromium.org/161303003/1

[commit-bot: I haz the power, 2014-02-12 22:46:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/adamk@chromium.org/161303003/1

[commit-bot: I haz the power, 2014-02-13 00:47:45]

Change committed as 167055