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..7d97aeb36857ac40565dfaa6e64d6a58fc25f1bb 100644
--- a/safari/ext/background.js
+++ b/safari/ext/background.js
@@ -154,6 +154,10 @@
     if (!(event.target instanceof SafariBrowserTab))
       return;
 
+    var activeTab = event.target.browserWindow.activeTab;
+    var pageId = addPage(activeTab, activeTab.url, false);
+    ext.pages.onActivated._dispatch(pages[pageId]);
+
     // 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
@@ -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)