Add an aura window property for Immersive fullscreen mode

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 14615fcdf8d0b2663af4c0dadd5fa4591c290193..3753bbdbc6b8d754bbd8b7f868536f15a44cc363 100644
--- a/services/ui/public/interfaces/window_manager.mojom
+++ b/services/ui/public/interfaces/window_manager.mojom
@@ -85,6 +85,11 @@ interface WindowManager {
   // used list of windows. Maps to aura::client::kExcludeFromMruKey. Type: bool.
   const string kExcludeFromMru_Property = "prop:exclude_from_mru";
 
+  // If true, when a window is in in fullscreen mode, the user cannot reveal
+  // the top portion of the window through a touch / mouse gesture.
+  // Type: bool.
+  const string kImmersiveFullscreen_Property = "prop:immersive-fullscreen";
+
   // Internal window name. Useful for debugging. Maps to aura::client::kNameKey.
   // Type: mojom::String
   const string kName_Property = "prop:name";