[Qt][WK2] Split the QtWebPageProxy into PageClient and QtPageProxy

[Qt][WK2] Split the QtWebPageProxy into PageClient and QtPageProxy
https://bugs.webkit.org/show_bug.cgi?id=66668

Reviewed by Simon Hausmann.

Split QtPageClient out of QtWebPageProxy.
This client will live in QQuickWebViewPrivate and communicate directly
with QtWebPageProxy and QtWebPageEventHandler. The functions that need
anything else than these entities will need to call the proper implementation
through QtWebPageProxy itself.
With this we have a clear separation between PageClient and PageProxy, having
two well defined and separated entities for hooking our clients with our API layer (QtWebPageProxy)
and for hooking the WebPageProxy with our client implementations (QtPageClient).
As a positive side-effect we have a cleaner QtWebPageProxy.

* Target.pri:
* UIProcess/API/qt/qquickwebview.cpp:
(QQuickWebViewPrivate::QQuickWebViewPrivate):
* UIProcess/API/qt/qquickwebview_p_p.h:
* UIProcess/qt/QtPageClient.cpp: Added.
(QtPageClient::QtPageClient):
(QtPageClient::~QtPageClient):
(QtPageClient::createDrawingAreaProxy):
(QtPageClient::setViewNeedsDisplay):
(QtPageClient::pageDidRequestScroll):
(QtPageClient::processDidCrash):
(QtPageClient::didRelaunchProcess):
(QtPageClient::didChangeContentsSize):
(QtPageClient::didChangeViewportProperties):
(QtPageClient::startDrag):
(QtPageClient::handleDownloadRequest):
(QtPageClient::setCursor):
(QtPageClient::setCursorHiddenUntilMouseMoves):
(QtPageClient::toolTipChanged):
(QtPageClient::registerEditCommand):
(QtPageClient::clearAllEditCommands):
(QtPageClient::canUndoRedo):
(QtPageClient::executeUndoRedo):
(QtPageClient::convertToDeviceSpace):
(QtPageClient::convertToUserSpace):
(QtPageClient::screenToWindow):
(QtPageClient::windowToScreen):
(QtPageClient::createPopupMenuProxy):
(QtPageClient::createContextMenuProxy):
(QtPageClient::flashBackingStoreUpdates):
(QtPageClient::didFindZoomableArea):
(QtPageClient::didReceiveMessageFromNavigatorQtObject):
(QtPageClient::doneWithTouchEvent):
(QtPageClient::displayView):
(QtPageClient::scrollView):
(QtPageClient::viewSize):
(QtPageClient::isViewWindowActive):
(QtPageClient::isViewFocused):
(QtPageClient::isViewVisible):
(QtPageClient::isViewInWindow):
(QtPageClient::enterAcceleratedCompositingMode):
(QtPageClient::exitAcceleratedCompositingMode):
* UIProcess/qt/QtPageClient.h: Added.
(QtPageClient::pageClosed):
(QtPageClient::doneWithKeyEvent):
(QtPageClient::setFindIndicator):
(QtPageClient::didCommitLoadForMainFrame):
(QtPageClient::didFinishLoadingDataForCustomRepresentation):
(QtPageClient::customRepresentationZoomFactor):
(QtPageClient::setCustomRepresentationZoomFactor):
(QtPageClient::didChangeScrollbarsForMainFrame):
(QtPageClient::findStringInCustomRepresentation):
(QtPageClient::countStringMatchesInCustomRepresentation):
(QtPageClient::setEventHandler):
(QtPageClient::setPageProxy):
* UIProcess/qt/QtWebPageProxy.cpp:
(QtWebPageProxy::QtWebPageProxy):
* UIProcess/qt/QtWebPageProxy.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@101788 268f45cc-cd09-0410-ab3c-d52691b4dbfc