Window: Disable transitions when changing window height to calculate content height

Otherwise we're getting values from when the window height is animating.

Not entirely sure why this fixes T72061, but the change definitely corrects
an error in our reasoning. It just happens to fix that bug, too.

Bug: T72061
Change-Id: I624f1b0da906200abefbbf914172b8794cdf4d1b
MessageDialog: Add Firefox hack for scrollbars when sizing dialogs

Firefox sometimes produces a scrollbar when the element doesn't need one
(http://i.imgur.com/8mpcLvw.png instead of http://i.imgur.com/gfJnz2J.png).
Temporarily killing it (with overflow: hidden), forcing reflow and then
restoring previous overflow value fixes it.

Bug: T72061
Change-Id: I8430cf6fc4da3c0f8fb4ab5bd6d2847834992d9b
Merge "Window: Disable transitions when changing window height to calculate content height"
Merge "MessageDialog: Add Firefox hack for scrollbars when sizing dialogs"