Bug 1588491 - Associate session history entries with a session history object from creation. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D49170

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extra : rebase_source : bc4c6e8cea0de7e85ae78ffb3ce09a7465e61b4a
extra : amend_source : 956bf8fa227e613b7f816dd5af9029ed24ba2c46
extra : source : 2d4b06fe1f429eec844cdeba8a7faaa63bfc25ab
extra : histedit_source : a2345826c7f94311ee57d805bf3ac9bed2e12ea7