Remove DocumentLoader::clearArchiveResources

It is possible for the DocumentLoader to lose it's ArchiveResourceCollection
without it's MHTMLArchive being deallocated as well, as is observed when a
navigation, which may be aborted, is initiated. By not clearing the
ArchiveResourceCollection in such cases, the DocumentLoader is left in a
still valid state.

BUG=348977

Review URL: https://codereview.chromium.org/183763030

git-svn-id: svn://svn.chromium.org/blink/trunk@170148 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed