Bug 986114 - Pre: introduce BaseRobocopTest, rework testBrowserProviderPerf. r=nalexander, a=lsblakk
Bug 986114 - Pre: clean up testReadingListProvider. r=trivial, a=lsblakk
Bug 986114 - Part 1: ReadingListProvider and BrowserProvider should share DB accessors. r=nalexander, a=lsblakk
Bug 986114 - Part 2: switch TabsProvider to use PerProfileDatabaseProvider. r=nalexander, a=lsblakk