Bug 1134399 - Make context-menu media commands use messages to avoid unsafe CPOW usage warnings. r=mconley

browser/base/content/content.js

@@ -1064,3 +1064,38 @@ addMessageListener("ContextMenu:SaveVideoFrameAsImage", (message) => {
     dataURL: canvas.toDataURL("image/jpeg", ""),
   });
 });
+
+addMessageListener("ContextMenu:MediaCommand", (message) => {
+  let media = message.objects.element;
+
+  switch (message.data.command) {
+    case "play":
+      media.play();
+      break;
+    case "pause":
+      media.pause();
+      break;
+    case "mute":
+      media.muted = true;
+      break;
+    case "unmute":
+      media.muted = false;
+      break;
+    case "playbackRate":
+      media.playbackRate = message.data.data;
+      break;
+    case "hidecontrols":
+      media.removeAttribute("controls");
+      break;
+    case "showcontrols":
+      media.setAttribute("controls", "true");
+      break;
+    case "hidestats":
+    case "showstats":
+      let event = media.ownerDocument.createEvent("CustomEvent");
+      event.initCustomEvent("media-showStatistics", false, true,
+                            message.data.command == "showstats");
+      media.dispatchEvent(event);
+      break;
+  }
+});

browser/base/content/nsContextMenu.js

@@ -1668,37 +1668,10 @@ nsContextMenu.prototype = {
   },
 
   mediaCommand : function CM_mediaCommand(command, data) {
-    var media = this.target;
-
-    switch (command) {
-      case "play":
-        media.play();
-        break;
-      case "pause":
-        media.pause();
-        break;
-      case "mute":
-        media.muted = true;
-        break;
-      case "unmute":
-        media.muted = false;
-        break;
-      case "playbackRate":
-        media.playbackRate = data;
-        break;
-      case "hidecontrols":
-        media.removeAttribute("controls");
-        break;
-      case "showcontrols":
-        media.setAttribute("controls", "true");
-        break;
-      case "hidestats":
-      case "showstats":
-        var event = media.ownerDocument.createEvent("CustomEvent");
-        event.initCustomEvent("media-showStatistics", false, true, command == "showstats");
-        media.dispatchEvent(event);
-        break;
-    }
+    let mm = this.browser.messageManager;
+    mm.sendAsyncMessage("ContextMenu:MediaCommand",
+                        {command: command, data: data},
+                        {element: this.target});
   },
 
   copyMediaLocation : function () {