[Qt] Handle the layers visible rect calculation on the web process.

[Qt] Handle the layers visible rect calculation on the web process.
https://bugs.webkit.org/show_bug.cgi?id=74720

Reviewed by Noam Rosenthal.

Source/WebCore:

Remove all visible rect calculation related code from TextureMapperNode.

* platform/graphics/texmap/TextureMapperNode.cpp:
* platform/graphics/texmap/TextureMapperNode.h:

Source/WebKit2:

The layers now get their visible rect on the web process through the
root layer when the UI process call setVisibleContentRectAndScale,
previously only used for the non-composited content layer.
The rect is then carried down the layers in the tree which apply it the inverse
of their transform before handing it to their tiled backing store.

This ensures that new layers get a proper visible rect right on creation,
and also that simultaneous visible rect and scale changes are applied synchronously.

This patch also uses clampedBoundsOfProjectedQuad instead of mapRect
to transform the visible rect correctly for 3D transformed layers.

* UIProcess/API/qt/qquickwebview.cpp:
(QQuickWebViewPrivate::initializeDesktop):
(QQuickWebViewPrivate::initializeTouch):
(QQuickWebViewPrivate::updateDesktopViewportSize):
(QQuickWebViewPrivate::updateTouchViewportSize):
(QQuickWebView::geometryChanged):
Make sure that the visible rect is updated for the desktop view as well.
* UIProcess/API/qt/qquickwebview_p_p.h:
* UIProcess/LayerTreeHostProxy.h:
* UIProcess/qt/LayerTreeHostProxyQt.cpp:
(WebKit::LayerTreeHostProxy::paintToCurrentGLContext):
* WebProcess/WebCoreSupport/WebGraphicsLayer.cpp:
(WebCore::WebGraphicsLayer::setChildren):
(WebCore::WebGraphicsLayer::addChild):
(WebCore::WebGraphicsLayer::addChildAtIndex):
(WebCore::WebGraphicsLayer::addChildAbove):
(WebCore::WebGraphicsLayer::addChildBelow):
(WebCore::WebGraphicsLayer::replaceChild):
(WebCore::WebGraphicsLayer::setMaskLayer):
(WebCore::WebGraphicsLayer::syncCompositingState):
(WebCore::WebGraphicsLayer::syncCompositingStateForThisLayerOnly):
(WebCore::WebGraphicsLayer::setVisibleContentRectAndScale):
(WebCore::WebGraphicsLayer::tiledBackingStoreVisibleRect):
(WebCore::WebGraphicsLayer::computeTransformedVisibleRect):
* WebProcess/WebCoreSupport/WebGraphicsLayer.h:
* WebProcess/WebPage/LayerTreeHost.messages.in:
* WebProcess/WebPage/qt/LayerTreeHostQt.cpp:
(WebKit::LayerTreeHostQt::setVisibleContentRectAndScale):
* WebProcess/WebPage/qt/LayerTreeHostQt.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105413 268f45cc-cd09-0410-ab3c-d52691b4dbfc