Expand and split DisplayController mojom.

services/ui/public/interfaces/display/display_controller.mojom

Index: services/ui/public/interfaces/display/display_controller.mojom
diff --git a/services/ui/public/interfaces/display/display_controller.mojom b/services/ui/public/interfaces/display/display_controller.mojom
index b9ae186dca3708d4c6225153a71e8f28155f42a4..1e2bd91c18aaf2d1e0026feeaa339f3bd42ecf48 100644
--- a/services/ui/public/interfaces/display/display_controller.mojom
+++ b/services/ui/public/interfaces/display/display_controller.mojom
@@ -4,13 +4,25 @@
 
 module display.mojom;
 
+import "ui/gfx/geometry/mojo/geometry.mojom";
+
 // An interface for clients that are allowed to make changes to the display 
 // state.
 interface DisplayController {
-  // Toggles adding or removing a virtual display. If there is only one display
+
+  // Toggles adding or removing a fake display. If there is only one display
   // a second display is added. If there is more than one display then the last
   // display is removed. 
-  ToggleVirtualDisplay();
+  ToggleAddRemoveDisplay();

[sky, 2016/10/13 18:11:23]

This is more of a testing api where as the other two aren't, right? Should we
move this into it's own interface to make that clear?

[kylechar, 2016/10/14 15:41:32]

Yes, it's definitely more of a testing API. If I moved it into a new interface,
it would be the only IPC in it though.

I think if I were to move ToggleAddRemoveDisplay into a separate interface I'd
want to change how it works? Have the new API be similar to
VirtualDisplayController, have Ctrl+Shift+D open a dedicated application that
connects to the new interface and has buttons to add/remove/modify displays for
testing. That would make it a bit more powerful. It's also very low priority
work.

+
+  // Swap the primary display and the next display.
+  SwapPrimaryDisplay();
+
+  // Sets the display work area with the provided insets. The display size is
+  // included to ensure that the insets are for the current display size.
+  SetDisplayWorkArea(int64 display_id, 
+                     gfx.mojom.Size size,
+                     gfx.mojom.Insets insets);
 
   // TODO(kylechar): This interface will need to be expanded to provide
   // additional functionality for the display settings page and other ash