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This was deprecated since M58 (having been replaced by
chrome://net-export/)

If users still have bookmarks to #export, they will now get a dialog
prompt asking them if they want to be redirected to
chrome://net-export/

BUG=678386
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2856223006
Cr-Commit-Position: refs/heads/master@{#469574}