1 files changed, 55 insertions, 0 deletions
diff --git a/browser/modules/ContentObservers.jsm b/browser/modules/ContentObservers.jsm
new file mode 100644
index 000000000..9d627ddc2
--- /dev/null
+++ b/browser/modules/ContentObservers.jsm
@@ -0,0 +1,55 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This module is for small observers that we want to register once per content
+ * process, usually in order to forward content-based observer service notifications
+ * to the chrome process through message passing. Using a JSM avoids having them
+ * in content.js and thereby registering N observers for N open tabs, which is bad
+ * for perf.
+ */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = [];
+
+const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+var gEMEUIObserver = function(subject, topic, data) {
+  let win = subject.top;
+  let mm = getMessageManagerForWindow(win);
+  if (mm) {
+    mm.sendAsyncMessage("EMEVideo:ContentMediaKeysRequest", data);
+  }
+};
+
+var gDecoderDoctorObserver = function(subject, topic, data) {
+  let win = subject.top;
+  let mm = getMessageManagerForWindow(win);
+  if (mm) {
+    mm.sendAsyncMessage("DecoderDoctor:Notification", data);
+  }
+};
+
+function getMessageManagerForWindow(aContentWindow) {
+  let ir = aContentWindow.QueryInterface(Ci.nsIInterfaceRequestor)
+                         .getInterface(Ci.nsIDocShell)
+                         .sameTypeRootTreeItem
+                         .QueryInterface(Ci.nsIInterfaceRequestor);
+  try {
+    // If e10s is disabled, this throws NS_NOINTERFACE for closed tabs.
+    return ir.getInterface(Ci.nsIContentFrameMessageManager);
+  } catch (e) {
+    if (e.result == Cr.NS_NOINTERFACE) {
+      return null;
+    }
+    throw e;
+  }
+}
+
+Services.obs.addObserver(gEMEUIObserver, "mediakeys-request", false);
+Services.obs.addObserver(gDecoderDoctorObserver, "decoder-doctor-notification", false);