Implement large cursors in Mushrome.

services/ui/public/interfaces/window_manager.mojom

Index: services/ui/public/interfaces/window_manager.mojom
diff --git a/services/ui/public/interfaces/window_manager.mojom b/services/ui/public/interfaces/window_manager.mojom
index e3896e35e942568b161c21f6fd65ba11db70cdda..65d492035d86c9ddebe39ea4ec3deae9c4a06a55 100644
--- a/services/ui/public/interfaces/window_manager.mojom
+++ b/services/ui/public/interfaces/window_manager.mojom
@@ -319,6 +319,9 @@ interface WindowManagerClient {
   // Shows and hides the cursor globally. Used during window management tasks.
   WmSetCursorVisible(bool visible);
 
+  // Sets whether we're using normal or large cursors.
+  WmSetCursorSet(CursorSet cursor_set);

[Tom Sepez, 2017/06/23 01:10:48]

What happens if a bad renderer changes to large (or vice versa) and continues to
use normal cursor methods (or vice versa)? 

[Elliot Glaysher, 2017/06/23 19:30:38]

I'm not sure I understand the question. This method is only available to the
window manager.

Let's say you have an untrusted renderer that sets its window's cursor to GRAB.
Mus keeps track of that data and will change the system cursor to GRAB when the
pointer is over that window. But what cursor will it use? A 1x cursor or a 2x?
That's what this method controls.

What happens if the renderer sets the cursor over its window to a small image
when using the large cursor set? It uses the renderer supplied data. This method
just controls selecting the size of inbuilt named cursors.

+
   // Sets a global cursor which overrides per-window cursors. Pass null to
   // clear.
   WmSetGlobalOverrideCursor(CursorData? cursor);