Windows style updates

[bsclifton]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Windows style updates

• Increases padding above menu by 2px

Windows 10 specific updates:

• window border was changed from black to the default blue accent color
• inactive windows now have their border set to gray

Fixes #4648

Auditors

@bradleyrichter - see screenshots
@bbondy, @bridiver - is this new window state/action ok? Since we'd like to migrate to appState, it can be done there too... but change is harder to make since focus/blur state for ALL windows needs to be tracked

Test plan

1. Launch Brave on Windows 10 and toggle the program menu
2. Notice that the height is 2px taller than before
3. Using the menu, open a new window
4. Notice that your new active window has a blue border and that the previous window has a gray border color

Screenshots:
extra padding over menu

new blue border + gray inactive border

[bbondy]

This is great, merging for 0.12.6.
It'd be nice to get a test for this, I think we could select a non focused window and check the bg color, but I'm not certain. Will merge for now in any case.