Surface synchronization: Don't gutter translucent windows

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 563697d642269a7c7935eb60a23deb00a568ad88..3ddbe2ce6567a53792741d58db14e6e18729dd78 100644
--- a/services/ui/public/interfaces/window_manager.mojom
+++ b/services/ui/public/interfaces/window_manager.mojom
@@ -44,6 +44,9 @@ interface WindowManager {
   // Whether the window should be initially focusable or not. Type: bool.
   const string kFocusable_InitProperty = "init:focusable";
 
+  // Whether the window should be opaque.
+  const string kTranslucent_InitProperty = "init:translucent";
+
   // Initial bounds to create the window at. If empty the WindowManager decides
   // the initial bounds. Type: gfx::Rect.
   const string kBounds_InitProperty = "init:bounds";