Add IPCs for ash display shortcuts.

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 c4e126d824ea64e82ef841089fe7ccfc44e2d51d..6ee1fbcf08fabeb2ff617d5cc7deba8ddbc29202 100644
--- a/services/ui/public/interfaces/display/display_controller.mojom
+++ b/services/ui/public/interfaces/display/display_controller.mojom
@@ -10,9 +10,29 @@ import "ui/gfx/geometry/mojo/geometry.mojom";
 // state.
 interface DisplayController {
 
+  // =========================== Keyboard Shortcuts ===========================
+
+  // Rotate the current display by 90° CW. The current display is the display
+  // closest to the mouse cursor.
+  RotateCurrentDisplay();

[James Cook, 2016/12/01 16:38:50]

How about calling this RotateCurrentDisplayCW() so it self-documents the
direction?

[kylechar, 2016/12/01 18:43:31]

Done.

+
   // Swap the primary display and the next display.
   SwapPrimaryDisplay();
 
+  // Toggles between mirroring and extended mode.
+  ToggleMirrorMode();
+
+  // Increase zoom on internal display.
+  ZoomInternalDisplayUp();

[James Cook, 2016/12/01 16:38:50]

As a non-graphics person I'm not sure if ZoomUp means making things look bigger
or smaller. Maybe ZoomInInternalDisplay? IncreaseInternalDisplayZoom for
symmetry with ResetInternalDisplayZoom?

[kylechar, 2016/12/01 18:43:31]

I agree, up/down doesn't make much sense. Changed.

+
+  // Decrease zoom on internal display.
+  ZoomInternalDisplayDown();
+
+  // Reset zoom on internal display to default level.
+  ResetInternalDisplayZoom();
+
+  // ========================= Configuration Changes ==========================
+
   // 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,