diff -r 000000000000 -r 6474c204b198 widget/cocoa/nsIdleServiceX.mm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/cocoa/nsIdleServiceX.mm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,77 @@
+/* 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/. */
+
+#include "nsIdleServiceX.h"
+#include "nsObjCExceptions.h"
+#include "nsIServiceManager.h"
+#import <Foundation/Foundation.h>
+
+NS_IMPL_ISUPPORTS_INHERITED0(nsIdleServiceX, nsIdleService)
+
+bool
+nsIdleServiceX::PollIdleTime(uint32_t *aIdleTime)
+{
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_RETURN;
+
+  kern_return_t rval;
+  mach_port_t masterPort;
+
+  rval = IOMasterPort(kIOMasterPortDefault, &masterPort);
+  if (rval != KERN_SUCCESS)
+    return false;
+
+  io_iterator_t hidItr;
+  rval = IOServiceGetMatchingServices(masterPort,
+                                      IOServiceMatching("IOHIDSystem"),
+                                      &hidItr);
+
+  if (rval != KERN_SUCCESS)
+    return false;
+  NS_ASSERTION(hidItr, "Our iterator is null, but it ought not to be!");
+
+  io_registry_entry_t entry = IOIteratorNext(hidItr);
+  NS_ASSERTION(entry, "Our IO Registry Entry is null, but it shouldn't be!");
+
+  IOObjectRelease(hidItr);
+
+  NSMutableDictionary *hidProps;
+  rval = IORegistryEntryCreateCFProperties(entry,
+                                           (CFMutableDictionaryRef*)&hidProps,
+                                           kCFAllocatorDefault, 0);
+  if (rval != KERN_SUCCESS)
+    return false;
+  NS_ASSERTION(hidProps, "HIDProperties is null, but no error was returned.");
+  [hidProps autorelease];
+
+  id idleObj = [hidProps objectForKey:@"HIDIdleTime"];
+  NS_ASSERTION([idleObj isKindOfClass: [NSData class]] ||
+               [idleObj isKindOfClass: [NSNumber class]],
+               "What we got for the idle object is not what we expect!");
+
+  uint64_t time;
+  if ([idleObj isKindOfClass: [NSData class]])
+    [idleObj getBytes: &time];
+  else
+    time = [idleObj unsignedLongLongValue];
+
+  IOObjectRelease(entry);
+
+  // convert to ms from ns
+  time /= 1000000;
+  if (time > UINT32_MAX) // Overflow will occur
+    return false;
+
+  *aIdleTime = static_cast<uint32_t>(time);
+
+  return true;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK_RETURN(false);
+}
+
+bool
+nsIdleServiceX::UsePollMode()
+{
+  return true;
+}
+