Updated ChromeDriver to latest (2017-02-06; v2.27)

[hnryjms]

Changelog to ChromeDriver:

----------ChromeDriver v2.27 (2016-12-23)----------
Supports Chrome v54-56
Resolved issue 1637: Getting window handles fails in the presence of shared workers on Chrome 55+ [['OS-All', 'Pri-1']]

----------ChromeDriver v2.26 (2016-12-09)----------
Supports Chrome v53-55
Resolved issue 1607: Chrome 57+ with perf logs enabled fails with "unexpected command response" [['OS-All', 'Pri-1']]
Resolved issue 1502: sendKeys(): SPACE key does not work on Chrome 53 [['OS-All', 'Pri-1']]
Resolved issue 984: Extend ChromeDriver capabilities to cover network throttling feature from Chrome DevTools [['OS-All', 'Pri-2']]
Resolved issue 877: UnhandledAlertException not being propagated upwards [['OS-All', 'Pri-2']]
Resolved issue 1578: Flash plugin blocked after updating Chrome browser [['OS-All', 'Pri-2']]
Resolved issue 1617: Fullscreen command is not recognised [['OS-All', 'Pri-3']]
Resolved issue 839: clear does not work on input type number with string value [['Pri-3']]
Resolved issue 1500: "Could not handle JavaScript dialog" error occurs randomly when accepting confirmation dialogs. [[]]
Resolved issue 1541: find element with empty tag is raising wrong exception in findElement [[]]
Resolved issue 1540: empty tagname value should raise an error when doing findElements [[]]

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[hnryjms]

Running make generate_all also included Firefox, so.....why not, ya know?

[hnryjms]

I'm also interested in how quickly this will get deployed to Docker Hub, as it might be related to #382 and #383 -- I've been seeing similar weirdness when the Chrome browser is running one of these newer versions.

[ddavison]

pushed the tag to our CI. if the tests pass, it will be put into docker hub immediately. thanks for this.

Also, please next time, only update the Dockerfile.txt files, and not the Dockerfiles :) thanks.