Bug 975162 - Remove empty destructuring let-block variable goofiness (r=wingo)

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extra : rebase_source : 39e6b59d4bca2cd547f0e43b34212ff5f967a85d
Bug 975162 - Remove block object's use of shortids (r=wingo)

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extra : rebase_source : 2babd344fba8aa17a51552dc756852096d2a5c67
Bug 797126 - Remove tinyid/shortid/userid (r=terrence)

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extra : rebase_source : d3cee5e71ca02708e91419b209b5914ce9fd2f9f