Dragging shouldn't block interstitial page.

content/browser/frame_host/interstitial_page_impl.cc

Index: content/browser/frame_host/interstitial_page_impl.cc
diff --git a/content/browser/frame_host/interstitial_page_impl.cc b/content/browser/frame_host/interstitial_page_impl.cc
index 10f99b4eadc3586208c6768500a0ec1ef3fdfff2..96650db8ea2f88b8ab7d5074e280d5df6f27828a 100644
--- a/content/browser/frame_host/interstitial_page_impl.cc
+++ b/content/browser/frame_host/interstitial_page_impl.cc
@@ -873,7 +873,8 @@ void InterstitialPageImpl::InterstitialPageRVHDelegateView::StartDragging(
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
     const DragEventSourceInfo& event_info) {
-  NOTREACHED() << "InterstitialPage does not support dragging yet.";
+  interstitial_page_->render_view_host_->DragSourceSystemDragEnded();
+  DVLOG(1) << "InterstitialPage does not support dragging yet.";
 }
 
 void InterstitialPageImpl::InterstitialPageRVHDelegateView::UpdateDragCursor(