https://bugs.webkit.org/show_bug.cgi?id=53639

Reviewed by Beth Dakin.

Source/WebCore: 

* page/Chrome.cpp:
(WebCore::ChromeClient::paintCustomOverhangArea):
* page/ChromeClient.h:
Add ChromeClient function.

* page/FrameView.cpp:
(WebCore::FrameView::paintOverhangAreas):
* page/FrameView.h:
Call out the the ChromeClient, call ScrollView base implementation
if the ChromeClient returns false.

* platform/ScrollView.cpp:
(WebCore::ScrollView::paintOverhangAreas):
* platform/ScrollView.h:
Add dirty rect for use when painting overhang areas.

Source/WebKit2: 

* Shared/API/c/WKBase.h:
* Shared/API/c/WKGraphicsContext.cpp: Added.
(WKGraphicsContextGetTypeID):
* Shared/API/c/WKGraphicsContext.h: Added.
* Shared/API/c/WKSharedAPICast.h:
* Shared/API/c/cg/WKGraphicsContextCG.cpp: Added.
(WKGraphicsContextGetCGContext):
* Shared/API/c/cg/WKGraphicsContextCG.h: Added.
* Shared/APIObject.h:
* Shared/WebGraphicsContext.cpp: Added.
(WebKit::WebGraphicsContext::WebGraphicsContext):
* Shared/WebGraphicsContext.h: Added.
(WebKit::WebGraphicsContext::create):
(WebKit::WebGraphicsContext::platformContext):
(WebKit::WebGraphicsContext::type):
Add WebGraphicsContext API type.

* WebProcess/InjectedBundle/API/c/WKBundlePage.h:
* WebProcess/InjectedBundle/InjectedBundlePageUIClient.cpp:
(WebKit::InjectedBundlePageUIClient::pageDidScroll):
(WebKit::InjectedBundlePageUIClient::shouldPaintCustomOverhangArea):
(WebKit::InjectedBundlePageUIClient::paintCustomOverhangArea):
* WebProcess/InjectedBundle/InjectedBundlePageUIClient.h:
* WebProcess/WebCoreSupport/WebChromeClient.cpp:
(WebKit::WebChromeClient::paintCustomOverhangArea):
* WebProcess/WebCoreSupport/WebChromeClient.h:
Pipe paintCustomOverhangArea to the InjectedBundlePageUIClient.

* UIProcess/API/C/WebKit2.h:
* WebKit2.pro:
* WebKit2.xcodeproj/project.pbxproj:
* win/WebKit2.vcproj:
* win/WebKit2Generated.make:
Add new files.

Tools: 

* WebKitTestRunner/InjectedBundle/InjectedBundlePage.cpp:
(WTR::InjectedBundlePage::InjectedBundlePage):
Stub out new callback.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@77432 268f45cc-cd09-0410-ab3c-d52691b4dbfc