Issue 3532 - Generate animation images at runtime

safari/ext/background.js

Index: safari/ext/background.js
diff --git a/safari/ext/background.js b/safari/ext/background.js
index e154aff029b37cedb5b06df6ed19f287e003aa48..9bbf25eb4875897b11a62da8a43c7a134002ced8 100644
--- a/safari/ext/background.js
+++ b/safari/ext/background.js
@@ -154,11 +154,15 @@
     if (!(event.target instanceof SafariBrowserTab))
       return;
 
+    let visiblePage = event.target._visiblePage;
+    if (visiblePage)
+      ext.pages.onActivated._dispatch(visiblePage);
+
     // update the toolbar item for the page visible in the tab that just
     // became active. If we can't find that page (e.g. when a page was
     // opened in a new tab, and our content script didn't run yet), the
     // toolbar item of the window, is reset to its intial configuration.
-    updateToolbarItemForPage(event.target._visiblePage, event.target.browserWindow);
+    updateToolbarItemForPage(visiblePage, event.target.browserWindow);
   }, true);
 
 
@@ -171,7 +175,7 @@
   {
     this._id = id;
     this._tab = tab;
-    this._frames = [{url: new URL(url), parent: null}];
+    this._frames = [{url: new URL(url || "about:blank"), parent: null}];
 
     if (tab.page)
       this._messageProxy = new ext._MessageProxy(tab.page);
@@ -293,7 +297,8 @@
 
       callback(matchedPages);
     },
-    onLoading: new ext._EventTarget()
+    onLoading: new ext._EventTarget(),
+    onActivated: new ext._EventTarget(),
   };
 
   safari.application.addEventListener("close", function(event)