Merge pull request #20575 from acperez/bug-1025829

Bug 1025829 - Browser single variant Top Sites are not ordered correctly.
Merge pull request #20681 from crdlc/bug-1026313

Bug 1026313 - [Vertical Homescreen] Icon gets stuck when dragging it near the home button
Merge pull request #20555 from crdlc/bug-1025835

Bug 1025835 - [Vertical Homescreen] Loading animation while downloading app is broken
Bug 1027185 - [email] switch manifest type back to certified
Merge pull request #20608 from crdlc/bug-1026257

Bug 1026257 - Would like to be able to set default number of columns in ...
Merge pull request #20657 from azasypkin/bug-1026528-corrupted-attachment

Bug 1026528 - [Messages] Corrupted attachments do not display correctly. r=julienw
Bug 1024933 - [Text Selection] Utility bubble's shadow improvement
Bug 1025633 - Update l10n ID of keyboard aria labels
Bug 1026369 - In import, contacts are duplicated.
Bug 1020264 - [flame] Status bar is displayed after launching video app and you can't play a video until it dissapears
Bug 1018495 - [Flame][Dialer] Missing headset icon when calling
Merge pull request #20581 from sergi/1023888

Bug 1023888 - When exporting contacts via bluetooth and cancelling, an error screen appears r=jmcanterafonseca
Merge pull request #20684 from ferjm/bug1023860.cancelmobileid

Bug 1023860 - Canceling the UI flow should clean up pending content requ...
Bug 1023940 - [Vertical]  Appy will-change only when dragging an icon r=crdlc
Merge pull request #20715 from KevinGrandon/bug_1023940_dragging_will_change

Bug 1023940 - [Vertical]  Appy will-change only when dragging an icon
Merge pull request #20408 from alivedise/bugzilla/1021658/turn-child-window-off

Bug 1021658 - Pref off in app sheet and disable popup on transitioning, r=etienne
Merge pull request #20615 from julienw/1016407-fix-calendar-test-with-new-mocha

Bug 1016407 - [Calendar] Fix unit tests with a newer mocha r=lightsofapo...
Merge pull request #20547 from alivedise/bugzilla/1023812_master/find-bottom-most-window-to-open-or-close

Bug 1023812 - Find bottom most window to do open/close operation when ac...r=timdream
Merge pull request #20691 from zacc/bug_941544

Bug 941544 - running_apps should always switch to System frame before ex...
Bug 1016431 - [System] Fix unit tests with a newer mocha r=alive