Workaround for #10124: change the title on close.

[busykai]

On Mac/OSX alert causes system modal dialog which prevents any interaction with
the browser and navigating away. This was causing unit tests to fail.

So instead of showing alert, change the title of the document to indicate that
the Live Preview session was closed. A more clear UI/UX definition is needed
for definitive solution.

Fixes #10124.

CC @redmunds

[redmunds]

@busykai In original extension, there's a custom overlay message displayed when browser is closed that I like -- why was that dropped?

[redmunds]

I'm still seeing 1 MultiBrowser (experimental) - LiveDevelopment unit test fail:

"should push in memory css changes made before the session starts"

TypeError: Cannot read property 'getSourceFromBrowser' of undefined
    at null.<anonymous> (file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/spec/LiveDevelopmentMultiBrowser-test.js:289:28)
    at jasmine.Block.execute (file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/thirdparty/jasmine-core/jasmine.js:1064:17)
    at jasmine.Queue.next_ (file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/thirdparty/jasmine-core/jasmine.js:2096:31)
    at onComplete (file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/thirdparty/jasmine-core/jasmine.js:2092:18)
    at jasmine.WaitsForBlock.execute (file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/thirdparty/jasmine-core/jasmine.js:2576:5)
    at file://localhost/Users/randyedmunds/github/brackets-shell/xcodebuild/Release/Brackets.app/Contents/dev/test/thirdparty/jasmine-core/jasmine.js:2590:12

timeout: timed out after 10000 msec waiting for Browser to sync changes

[busykai]

@redmunds which Safari version do you use? I have 8.0.2 (10600.3.8.2), running on OSX 10.10.

[redmunds]

I have Safari Version 6.2 (8537.85.10.17.1) on Mac OS X 10.8.5 .

[busykai]

OK. Let me try to find a similar Mac... If I won't be able to resolve it today, we'll have to turn off that test.

As for overlay, I am not exactly sure why it was dropped. I can add it back. We never knew, however, how this implementation should indicate it's been closed. Changing title in addition to the overlay might be actually a good idea.

[busykai]

Got it reproduced on OSX 10.9.4 with Safari 7.0.5. However, I think the issue is not the version, but how fast is the machine itself. The issue is that the css is not yet registered as related document and LiveDevelopment.getLiveDocForPath. I'm going to exclude it for now and make sure it fixed ASAP.

The overlay in the original extension was not nice, actually, but I've reworked it a little bit and included here.

[redmunds]

FWIW, this is a 2 year old MacBook Pro Retina, so it's fast. I just kept the version at 10.8 for testing coverage. Maybe it's an OS difference.

Anyway, looks good. Merging.