Remove Downcasting RVContextMenuBase in ContextMenuDeleagate implementations.

content/public/common/context_menu_params.h

Index: content/public/common/context_menu_params.h
diff --git a/content/public/common/context_menu_params.h b/content/public/common/context_menu_params.h
index 8849dae303d29f4677075080dd1a289698103a22..290d9e566cfaf452d91e791d091e2a9d4f43d9a9 100644
--- a/content/public/common/context_menu_params.h
+++ b/content/public/common/context_menu_params.h
@@ -61,6 +61,11 @@ struct CONTENT_EXPORT ContextMenuParams {
   int x;
   int y;
 
+  // These values represent the screen coordicates of the mouse when the
+  // context menu was invoked.  These values are set in the browser/.
+  float screen_x;

[sky, 2014/10/27 19:24:53]

These should be set in content before the params are passed to the delegate.

[lazyboy, 2014/10/27 22:01:13]

I just hit a bump while doing this in RenderFrameHostImpl::OnContextMenu()

aura uses screen coordinates to bring up the context menu,
but mac actually doesn't, it rather requires coordinates within window
with y flipped so that 0 is at the bottom edge :(

In this case, calling this screen_x/y makes things confusing.
How about view_x/y?

My current plan is:
Add
virtual gfx::PointF
RenderWidgetHostViewBase::ConvertPointToContextMenuCoordinates() = 0;

and change:
RenderFrameHostImpl::OnContextMenu(ContextMenuParams params) {
  ..
  gfx::PointF view_point =
      render_view_host_->GetView()->ConvertPointToContextMenuCoordinates(
          gfx::Point(params.x, params.y));
  params.view_x = view_point.x();
  params.view_y = view_point.y();

  delegate_->ShowContextMenu(this, params);  
}

WDYT?

+  float screen_y;
+
   // This is the URL of the link that encloses the node the context menu was
   // invoked on.
   GURL link_url;