Enable visibleOnAllWorkspaces on stable.

extensions/common/api/app_window.idl

Index: extensions/common/api/app_window.idl
diff --git a/extensions/common/api/app_window.idl b/extensions/common/api/app_window.idl
index b8f94fcad8e9b666d4421b3164f585b2e6bbd139..18247037a781c4c7efc1bf03d9c39a4faef0dedd 100644
--- a/extensions/common/api/app_window.idl
+++ b/extensions/common/api/app_window.idl
@@ -272,7 +272,6 @@ namespace app.window {
     boolean? focused;
 
     // If true, the window will be visible on all workspaces.
-    // This is only available on dev channel.
     boolean? visibleOnAllWorkspaces;
   };
 
@@ -391,7 +390,6 @@ namespace app.window {
 
     // For platforms that support multiple workspaces, is this window visible on
     // all of them?
-    // This is only available on dev channel.
     static void setVisibleOnAllWorkspaces(boolean alwaysVisible);
 
     // Set whether the window should get all keyboard events including system