https://bugs.webkit.org/show_bug.cgi?id=105516
<rdar://problem/12729443>

Reviewed by Alexey Proskuryakov.

Add shouldAllowNavigationFromDrags to Plugin/PluginView/etc., which WebCore will
consult when dragging over a PluginDocument to decide whether or not a drag may result in navigation.

* WebProcess/Plugins/Netscape/NetscapePlugin.cpp:
(WebKit::NetscapePlugin::shouldAllowNavigationFromDrags): Added, always returning false to keep existing behavior.
* WebProcess/Plugins/Netscape/NetscapePlugin.h:
(NetscapePlugin): Added.
* WebProcess/Plugins/PDF/SimplePDFPlugin.h:
(WebKit::SimplePDFPlugin::shouldAllowNavigationFromDrags): Added, always returning true. (Simple)PDFPlugin should
navigate when dropped onto, just like an image or HTML document would.
* WebProcess/Plugins/Plugin.h:
(Plugin): Add shouldAllowNavigationFromDrags.
* WebProcess/Plugins/PluginProxy.h: Add shouldAllowNavigationFromDrags.
* WebProcess/Plugins/PluginView.cpp:
(WebKit::PluginView::shouldAllowNavigationFromDrags): Forward shouldAllowNavigationFromDrags to the plugin.
* WebProcess/Plugins/PluginView.h: Add shouldAllowNavigationFromDrags.

* page/DragController.cpp:
(WebCore::DragController::operationForLoad): If we drag over a PluginDocument, check if its PluginView
claims to support navigation resulting from a drag (only PDFPlugin will for now). If it does, allow the drag.
* plugins/PluginViewBase.h:
(WebCore::PluginViewBase::shouldAllowNavigationFromDrags): Add shouldAllowNavigationFromDrags.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@138361 268f45cc-cd09-0410-ab3c-d52691b4dbfc