WebDriver: rename m_browsingContext as m_currentBrowsingContext in Session

WebDriver: rename m_browsingContext as m_currentBrowsingContext in Session
https://bugs.webkit.org/show_bug.cgi?id=174783

Patch by Carlos Garcia Campos <cgarcia@igalia.com> on 2017-07-24
Reviewed by Brian Burg.

We have m_toplevelBrowsingContext and m_browsingContext, which is confusing. m_browsingContext is actually the
current browsing context, and the spec also refers to it as the current browsing context, so better use
m_currentBrowsingContext.

* Session.cpp:
(WebDriver::Session::switchToTopLevelBrowsingContext):
(WebDriver::Session::switchToBrowsingContext):
(WebDriver::Session::switchToFrame):
(WebDriver::Session::switchToParentFrame):
(WebDriver::Session::computeElementLayout):
(WebDriver::Session::findElements):
(WebDriver::Session::isElementSelected):
(WebDriver::Session::getElementText):
(WebDriver::Session::getElementTagName):
(WebDriver::Session::isElementEnabled):
(WebDriver::Session::isElementDisplayed):
(WebDriver::Session::getElementAttribute):
(WebDriver::Session::waitForNavigationToComplete):
(WebDriver::Session::elementClear):
(WebDriver::Session::elementSendKeys):
(WebDriver::Session::elementSubmit):
(WebDriver::Session::executeScript):
* Session.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@219833 268f45cc-cd09-0410-ab3c-d52691b4dbfc