Page::instanceHandle into its own file just in the WebCore 
namespace.

Reviewed by Anders Carlsson.

Added WebCoreInstanceHandle.h + .cpp and removed PageWin.cpp
* WebCore.vcproj/WebCore.vcproj:
* page/win/PageWin.cpp: Removed.

Remove all instance handle code from Page.
* page/Page.h:

New files.
* platform/win/WebCoreInstanceHandle.cpp: Added.
* platform/win/WebCoreInstanceHandle.h: Added.
(WebCore::setInstanceHandle):
(WebCore::instanceHandle):

Switch to WebCore::instanceHandle() instead of 
Page::instanceHandle() and include the new header.
* platform/graphics/win/WKCACFLayerRenderer.cpp:
(WebCore::WKCACFLayerRenderer::acceleratedCompositingAvailable):
* platform/win/PasteboardWin.cpp:
(WebCore::Pasteboard::Pasteboard):
* platform/win/PopupMenuWin.cpp:
(WebCore::PopupMenu::show):
(WebCore::PopupMenu::registerClass):
* platform/win/SharedTimerWin.cpp:
(WebCore::initializeOffScreenTimerWindow):
* plugins/win/PluginViewWin.cpp:
(WebCore::registerPluginView):
(WebCore::PluginView::platformStart):

WebKit/win: WebCore::Page::setInstanceHandle() is now just 
WebCore::setInstanceHandle()

Reviewed by Anders Carlsson.

* WebKitDLL.cpp:
(DllMain):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55542 268f45cc-cd09-0410-ab3c-d52691b4dbfc