Bug 843889 - pre: Move log tests to org.mozilla.gecko.background hierarchy.
Bug 843889 - Delete StubActivity.
Bug 843889 - Factor CursorDumper out of RepoUtils.
Bug 843889 - Factor Tab out of TabsRecord.
Bug 843889 - Move Android Sync-specific Tab JSON manipulation into TabsRecord.
Bug 843889 - Move Tab into org.mozilla.gecko.background.db.
Bug 843889 - Move FennecTabsRepository.tabFromCursor to Tab.fromCursor.
Bug 843889 - Separate Sync-specific TestTabsRecord out of Fennec-exercising TestFennecTabsStorage.
Bug 843889 - Move TestFennecTabsStorage to org.mozilla.gecko.background.db.test.
Bug 843889 - Factor tabs code that is not Sync-specific out of org.mozilla.gecko.sync. r=rnewman