https://bugs.webkit.org/show_bug.cgi?id=110299

Patch by Huang Dongsung <luxtella@company100.net> on 2013-02-20
Reviewed by Anders Carlsson.

Currently, we call setNeedsDisplay with the size of WebPage to mark whole
backing store as dirty. However, the size of non compositing layer can be
inconsistent with the size of WebPage. For example, in Coordinated Graphics, the
size of non compositing layer is contents size.

So, WebPage should not assume the size of non compositing layer, and should just
call setNeedsDisplay when marking whole layer as dirty.

In addition, this patch renames from setNeedsDisplay() with a rect argument to
setNeedsDisplayInRect(), which matches to the terms of GraphicsLayer.

* WebProcess/WebCoreSupport/WebChromeClient.cpp:
(WebKit::WebChromeClient::invalidateContentsAndRootView):
(WebKit::WebChromeClient::invalidateContentsForSlowScroll):
* WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp:
(WebKit::WebFrameLoad...