[Qt] [WK2] Expose web view classes to QML

[Qt] [WK2] Expose web view classes to QML
https://bugs.webkit.org/show_bug.cgi?id=65339

Reviewed by Benjamin Poulain.

.:

* Source/WebKit.pro: Include QML plugin subdir in the build system for WK2.

Source/WebKit2:

This patch also uses QuickTest from QtDeclarative to provide the basic autotest
infrastructure for the exposed elements.

* UIProcess/API/qt/qmlplugin/plugin.cpp: Added.
(WebKit2QmlPlugin::registerTypes):
* UIProcess/API/qt/qmlplugin/qmldir: Added.
* UIProcess/API/qt/qmlplugin/qmlplugin.pro: Added.
* UIProcess/API/qt/qtouchwebpage.h: Expose load() to QML environment.
* UIProcess/API/qt/qtouchwebview.h: Since QTouchWebPage* doesn't change once set
in the constructor, we mark the page property as CONSTANT. This avoid QML
warnings for not having a NOTIFY signal for the property change.

* UIProcess/API/qt/tests/tests.pro:
* UIProcess/API/qt/tests/qmltests/DesktopWebView/tst_properties.qml: Added.
* UIProcess/API/qt/tests/qmltests/TouchWebView/tst_properties.qml: Added.
* UIProcess/API/qt/tests/qmltests/common/test1.html: Added.
* UIProcess/API/qt/tests/qmltests/qmltests.pro: Added.
* UIProcess/API/qt/tests/qmltests/tst_qmltests.cpp: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@92277 268f45cc-cd09-0410-ab3c-d52691b4dbfc