--- a/content/events/src/nsDOMGamepad.cpp
+++ b/content/events/src/nsDOMGamepad.cpp
@@ -1,56 +1,46 @@
 /* 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 "nsDOMGamepad.h"
-#include "nsDOMClassInfoID.h"
-#include "nsIClassInfo.h"
-#include "nsIXPCScriptable.h"
+#include "nsAutoPtr.h"
 #include "nsTArray.h"
 #include "nsContentUtils.h"
 #include "nsVariant.h"
+#include "mozilla/dom/GamepadBinding.h"
 
-DOMCI_DATA(Gamepad, nsDOMGamepad)
+using namespace mozilla;
+using namespace mozilla::dom;
 
-NS_IMPL_ADDREF(nsDOMGamepad)
-NS_IMPL_RELEASE(nsDOMGamepad)
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMGamepad)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMGamepad)
 
-NS_INTERFACE_MAP_BEGIN(nsDOMGamepad)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMGamepad)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
   NS_INTERFACE_MAP_ENTRY(nsISupports)
   NS_INTERFACE_MAP_ENTRY(nsIDOMGamepad)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(Gamepad)
 NS_INTERFACE_MAP_END
 
-nsDOMGamepad::nsDOMGamepad(const nsAString& aID, uint32_t aIndex,
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(nsDOMGamepad, mParent)
+
+nsDOMGamepad::nsDOMGamepad(nsISupports* aParent,
+                           const nsAString& aID, uint32_t aIndex,
                            uint32_t aNumButtons, uint32_t aNumAxes)
-  : mID(aID),
+  : mParent(aParent),
+    mID(aID),
     mIndex(aIndex),
     mConnected(true)
 {
+  SetIsDOMBinding();
   mButtons.InsertElementsAt(0, aNumButtons, 0);
   mAxes.InsertElementsAt(0, aNumAxes, 0.0f);
 }
 
-/* readonly attribute DOMString id; */
-NS_IMETHODIMP
-nsDOMGamepad::GetId(nsAString& aID)
-{
-  aID = mID;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDOMGamepad::GetIndex(uint32_t* aIndex)
-{
-  *aIndex = mIndex;
-  return NS_OK;
-}
-
 void
 nsDOMGamepad::SetIndex(uint32_t aIndex)
 {
   mIndex = aIndex;
 }
 
 void
 nsDOMGamepad::SetConnected(bool aConnected)
@@ -67,26 +57,17 @@ nsDOMGamepad::SetButton(uint32_t aButton
 
 void
 nsDOMGamepad::SetAxis(uint32_t aAxis, double aValue)
 {
   MOZ_ASSERT(aAxis < mAxes.Length());
   mAxes[aAxis] = aValue;
 }
 
-/* readonly attribute boolean connected; */
-NS_IMETHODIMP
-nsDOMGamepad::GetConnected(bool* aConnected)
-{
-  *aConnected = mConnected;
-  return NS_OK;
-}
-
-/* readonly attribute nsIVariant buttons; */
-NS_IMETHODIMP
+nsresult
 nsDOMGamepad::GetButtons(nsIVariant** aButtons)
 {
   nsRefPtr<nsVariant> out = new nsVariant();
   NS_ENSURE_STATE(out);
 
   if (mButtons.Length() == 0) {
     nsresult rv = out->SetAsEmptyArray();
     NS_ENSURE_SUCCESS(rv, rv);
@@ -107,18 +88,17 @@ nsDOMGamepad::GetButtons(nsIVariant** aB
     NS_Free(array);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   *aButtons = out.forget().get();
   return NS_OK;
 }
 
-/* readonly attribute nsIVariant axes; */
-NS_IMETHODIMP
+nsresult
 nsDOMGamepad::GetAxes(nsIVariant** aAxes)
 {
   nsRefPtr<nsVariant> out = new nsVariant();
   NS_ENSURE_STATE(out);
 
   if (mAxes.Length() == 0) {
     nsresult rv = out->SetAsEmptyArray();
     NS_ENSURE_SUCCESS(rv, rv);
@@ -157,15 +137,21 @@ nsDOMGamepad::SyncState(nsDOMGamepad* aO
     mButtons[i] = aOther->mButtons[i];
   }
   for (uint32_t i = 0; i < mAxes.Length(); ++i) {
     mAxes[i] = aOther->mAxes[i];
   }
 }
 
 already_AddRefed<nsDOMGamepad>
-nsDOMGamepad::Clone()
+nsDOMGamepad::Clone(nsISupports* aParent)
 {
   nsRefPtr<nsDOMGamepad> out =
-    new nsDOMGamepad(mID, mIndex, mButtons.Length(), mAxes.Length());
+    new nsDOMGamepad(aParent, mID, mIndex, mButtons.Length(), mAxes.Length());
   out->SyncState(this);
   return out.forget();
 }
+
+/* virtual */ JSObject*
+nsDOMGamepad::WrapObject(JSContext* aCx, JSObject* aScope)
+{
+  return GamepadBinding::Wrap(aCx, aScope, this);
+}

--- a/content/events/src/nsDOMGamepad.h
+++ b/content/events/src/nsDOMGamepad.h
@@ -1,45 +1,91 @@
 /* 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/. */
 
 #ifndef nsDomGamepad_h
 #define nsDomGamepad_h
 
+#include "mozilla/ErrorResult.h"
 #include "mozilla/StandardInteger.h"
+#include "nsCOMPtr.h"
 #include "nsIDOMGamepad.h"
 #include "nsString.h"
-#include "nsCOMPtr.h"
 #include "nsTArray.h"
+#include "nsWrapperCache.h"
 
 class nsDOMGamepad : public nsIDOMGamepad
+                   , public nsWrapperCache
 {
 public:
-  nsDOMGamepad(const nsAString& aID, uint32_t aIndex,
+  nsDOMGamepad(nsISupports* aParent,
+               const nsAString& aID, uint32_t aIndex,
                uint32_t aNumButtons, uint32_t aNumAxes);
-  NS_DECL_ISUPPORTS
-  NS_DECL_NSIDOMGAMEPAD
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsDOMGamepad)
 
   nsDOMGamepad();
   void SetConnected(bool aConnected);
   void SetButton(uint32_t aButton, double aValue);
   void SetAxis(uint32_t aAxis, double aValue);
   void SetIndex(uint32_t aIndex);
 
   // Make the state of this gamepad equivalent to other.
   void SyncState(nsDOMGamepad* other);
 
-  // Return a new nsDOMGamepad containing the same data as this object.
-  already_AddRefed<nsDOMGamepad> Clone();
+  // Return a new nsDOMGamepad containing the same data as this object,
+  // parented to aParent.
+  already_AddRefed<nsDOMGamepad> Clone(nsISupports* aParent);
+
+  nsISupports* GetParentObject() const
+  {
+    return mParent;
+  }
+
+  virtual JSObject*
+  WrapObject(JSContext* aCx, JSObject* aScope) MOZ_OVERRIDE;
+
+  void GetId(nsAString& aID) const
+  {
+    aID = mID;
+  }
+
+  bool Connected() const
+  {
+    return mConnected;
+  }
+
+  uint32_t Index() const
+  {
+    return mIndex;
+  }
+
+  already_AddRefed<nsIVariant> GetButtons(mozilla::ErrorResult& aRv)
+  {
+    nsCOMPtr<nsIVariant> buttons;
+    aRv = GetButtons(getter_AddRefs(buttons));
+    return buttons.forget();
+  }
+
+  already_AddRefed<nsIVariant> GetAxes(mozilla::ErrorResult& aRv)
+  {
+    nsCOMPtr<nsIVariant> axes;
+    aRv = GetAxes(getter_AddRefs(axes));
+    return axes.forget();
+  }
 
 private:
   virtual ~nsDOMGamepad() {}
 
+  nsresult GetButtons(nsIVariant** aButtons);
+  nsresult GetAxes(nsIVariant** aAxes);
+
 protected:
+  nsCOMPtr<nsISupports> mParent;
   nsString mID;
   uint32_t mIndex;
 
   // true if this gamepad is currently connected.
   bool mConnected;
 
   // Current state of buttons, axes.
   nsTArray<double> mButtons;

--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -213,19 +213,16 @@
 #include "nsIDOMCRMFObject.h"
 #include "nsIDOMCryptoLegacy.h"
 #else
 #include "nsIDOMCrypto.h"
 #endif
 #include "nsIControllers.h"
 #include "nsISelection.h"
 #include "nsIBoxObject.h"
-#ifdef MOZ_GAMEPAD
-#include "nsIDOMGamepad.h"
-#endif
 #ifdef MOZ_XUL
 #include "nsITreeSelection.h"
 #include "nsITreeContentView.h"
 #include "nsITreeView.h"
 #include "nsIXULTemplateBuilder.h"
 #include "nsTreeColumns.h"
 #endif
 #include "nsIDOMXPathExpression.h"
@@ -968,21 +965,16 @@ static nsDOMClassInfoData sClassInfoData
 
   NS_DEFINE_CLASSINFO_DATA(Touch, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(TouchList, nsDOMTouchListSH,
                            ARRAY_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(TouchEvent, nsEventSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
-#ifdef MOZ_GAMEPAD
-  NS_DEFINE_CLASSINFO_DATA(Gamepad, nsDOMGenericSH,
-                           DOM_DEFAULT_SCRIPTABLE_FLAGS)
-#endif
-
   NS_DEFINE_CLASSINFO_DATA(MozCSSKeyframeRule, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(MozCSSKeyframesRule, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
   NS_DEFINE_CLASSINFO_DATA(CSSPageRule, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
@@ -2469,22 +2461,16 @@ nsDOMClassInfo::Init()
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN_MAYBE_DISABLE(TouchEvent, nsIDOMTouchEvent,
                                         !nsDOMTouchEvent::PrefEnabled())
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMTouchEvent)
     DOM_CLASSINFO_UI_EVENT_MAP_ENTRIES
   DOM_CLASSINFO_MAP_END
 
-#ifdef MOZ_GAMEPAD
-  DOM_CLASSINFO_MAP_BEGIN(Gamepad, nsIDOMGamepad)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMGamepad)
-  DOM_CLASSINFO_MAP_END
-#endif
-
   DOM_CLASSINFO_MAP_BEGIN(MozCSSKeyframeRule, nsIDOMMozCSSKeyframeRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozCSSKeyframeRule)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(MozCSSKeyframesRule, nsIDOMMozCSSKeyframesRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozCSSKeyframesRule)
   DOM_CLASSINFO_MAP_END
 

--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -233,20 +233,16 @@ DOMCI_CLASS(IDBKeyRange)
 DOMCI_CLASS(IDBIndex)
 DOMCI_CLASS(IDBVersionChangeEvent)
 DOMCI_CLASS(IDBOpenDBRequest)
 
 DOMCI_CLASS(Touch)
 DOMCI_CLASS(TouchList)
 DOMCI_CLASS(TouchEvent)
 
-#ifdef MOZ_GAMEPAD
-DOMCI_CLASS(Gamepad)
-#endif
-
 DOMCI_CLASS(MozCSSKeyframeRule)
 DOMCI_CLASS(MozCSSKeyframesRule)
 
 DOMCI_CLASS(CSSPageRule)
 
 DOMCI_CLASS(MediaQueryList)
 
 #ifdef MOZ_B2G_RIL

--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -1484,16 +1484,20 @@ nsGlobalWindow::FreeInnerObjects()
   NotifyWindowIDDestroyed("inner-window-destroyed");
 
   CleanupCachedXBLHandlers(this);
 
   for (uint32_t i = 0; i < mAudioContexts.Length(); ++i) {
     mAudioContexts[i]->Shutdown();
   }
   mAudioContexts.Clear();
+
+#ifdef MOZ_GAMEPAD
+  mGamepads.Clear();
+#endif
 }
 
 //*****************************************************************************
 // nsGlobalWindow::nsISupports
 //*****************************************************************************
 
 #define OUTER_WINDOW_ONLY                                                     \
   if (IsOuterWindow()) {
@@ -1626,16 +1630,20 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStorage)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mApplicationCache)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocumentPrincipal)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDoc)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIdleService)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPendingStorageEvents)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIdleObservers)
 
+#ifdef MOZ_GAMEPAD
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mGamepads)
+#endif
+
   // Traverse stuff from nsPIDOMWindow
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mChromeEventHandler)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParentTarget)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFrameElement)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFocusedNode)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAudioContexts)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
@@ -1669,16 +1677,20 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(ns
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStorage)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mApplicationCache)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocumentPrincipal)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mDoc)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mIdleService)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mPendingStorageEvents)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mIdleObservers)
 
+#ifdef MOZ_GAMEPAD
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mGamepads)
+#endif
+
   // Unlink stuff from nsPIDOMWindow
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mChromeEventHandler)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mParentTarget)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFrameElement)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFocusedNode)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mAudioContexts)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END

--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -362,16 +362,20 @@ DOMInterfaces = {
     'nativeType': 'JSObject'
 }],
 
 'GainNode': {
     'resultNotAddRefed': [ 'gain' ],
     'wrapperCache': False
 },
 
+'Gamepad': {
+    'nativeType': 'nsDOMGamepad',
+},
+
 'HTMLAppletElement': {
     'nativeType': 'mozilla::dom::HTMLSharedObjectElement'
 },
 
 'HTMLBaseElement': {
     'nativeType': 'mozilla::dom::HTMLSharedElement'
 },
 
@@ -1453,16 +1457,17 @@ addExternalIface('MozRDFCompositeDataSou
                  notflattened=True)
 addExternalIface('MozRDFResource', nativeType='nsIRDFResource', notflattened=True)
 addExternalIface('MozXULTemplateBuilder', nativeType='nsIXULTemplateBuilder')
 addExternalIface('MozNamedAttrMap')
 addExternalIface('nsIControllers', nativeType='nsIControllers')
 addExternalIface('nsIStreamListener', nativeType='nsIStreamListener', notflattened=True)
 addExternalIface('nsISupports', nativeType='nsISupports')
 addExternalIface('nsIEditor', nativeType='nsIEditor', notflattened=True)
+addExternalIface('nsIVariant', nativeType='nsIVariant', notflattened=True)
 addExternalIface('OutputStream', nativeType='nsIOutputStream',
                  notflattened=True)
 addExternalIface('Principal', nativeType='nsIPrincipal',
                  headerFile='nsIPrincipal.h', notflattened=True)
 addExternalIface('Selection', nativeType='nsISelection')
 addExternalIface('StyleSheetList')
 addExternalIface('SVGAnimatedEnumeration', headerFile='nsIDOMSVGAnimatedEnum.h')
 addExternalIface('SVGAnimatedNumber')

--- a/dom/interfaces/gamepad/nsIDOMGamepad.idl
+++ b/dom/interfaces/gamepad/nsIDOMGamepad.idl
@@ -4,36 +4,9 @@
 
 #include "nsISupports.idl"
 
 interface nsIVariant;
 
 [builtinclass, scriptable, uuid(ff13acd9-11da-4817-8f2a-4a5700dfd13e)]
 interface nsIDOMGamepad : nsISupports
 {
-  /**
-   * An identifier, unique per type of device.
-   */
-  readonly attribute DOMString id;
-
-  /**
-   * The game port index for the device. Unique per device
-   * attached to this system.
-   */
-  readonly attribute unsigned long index;
-
-  /**
-   * true if this gamepad is currently connected to the system.
-   */
-  readonly attribute boolean connected;
-
-  /**
-   * The current state of all buttons on the device, an
-   * array of doubles.
-   */
-  readonly attribute nsIVariant buttons;
-
-  /**
-   * The current position of all axes on the device, an
-   * array of doubles.
-   */
-  readonly attribute nsIVariant axes;
 };

--- a/dom/system/GamepadService.cpp
+++ b/dom/system/GamepadService.cpp
@@ -128,17 +128,18 @@ GamepadService::RemoveListener(nsGlobalW
 
 uint32_t
 GamepadService::AddGamepad(const char* aId,
                            uint32_t aNumButtons,
                            uint32_t aNumAxes)
 {
   //TODO: bug 852258: get initial button/axis state
   nsRefPtr<nsDOMGamepad> gamepad =
-    new nsDOMGamepad(NS_ConvertUTF8toUTF16(nsDependentCString(aId)),
+    new nsDOMGamepad(nullptr,
+                     NS_ConvertUTF8toUTF16(nsDependentCString(aId)),
                      0,
                      aNumButtons,
                      aNumAxes);
   int index = -1;
   for (uint32_t i = 0; i < mGamepads.Length(); i++) {
     if (!mGamepads[i]) {
       mGamepads[i] = gamepad;
       index = i;
@@ -408,17 +409,18 @@ GamepadService::SetWindowHasSeenGamepad(
 {
   if (mListeners.IndexOf(aWindow) == NoIndex) {
     // This window isn't even listening for gamepad events.
     return;
   }
 
   if (aHasSeen) {
     aWindow->SetHasSeenGamepadInput(true);
-    nsRefPtr<nsDOMGamepad> gamepad = mGamepads[aIndex]->Clone();
+    nsCOMPtr<nsISupports> window = nsGlobalWindow::ToSupports(aWindow);
+    nsRefPtr<nsDOMGamepad> gamepad = mGamepads[aIndex]->Clone(window);
     aWindow->AddGamepad(aIndex, gamepad);
   } else {
     aWindow->RemoveGamepad(aIndex);
   }
 }
 
 // static
 void

new file mode 100644
--- /dev/null
+++ b/dom/webidl/Gamepad.webidl
@@ -0,0 +1,37 @@
+/* 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/. */
+
+interface nsIVariant;
+
+interface Gamepad {
+  /**
+   * An identifier, unique per type of device.
+   */
+  readonly attribute DOMString id;
+
+  /**
+   * The game port index for the device. Unique per device
+   * attached to this system.
+   */
+  readonly attribute unsigned long index;
+
+  /**
+   * true if this gamepad is currently connected to the system.
+   */
+  readonly attribute boolean connected;
+
+  /**
+   * The current state of all buttons on the device, an
+   * array of doubles.
+   */
+  [Throws]
+  readonly attribute nsIVariant buttons;
+
+  /**
+   * The current position of all axes on the device, an
+   * array of doubles.
+   */
+  [Throws]
+  readonly attribute nsIVariant axes;
+};

--- a/dom/webidl/WebIDL.mk
+++ b/dom/webidl/WebIDL.mk
@@ -66,16 +66,17 @@ webidl_files = \
   File.webidl \
   FileHandle.webidl \
   FileList.webidl \
   FileReaderSync.webidl \
   FileRequest.webidl \
   FormData.webidl \
   Function.webidl \
   GainNode.webidl \
+  Gamepad.webidl \
   HTMLAnchorElement.webidl \
   HTMLAppletElement.webidl \
   HTMLAreaElement.webidl \
   HTMLAudioElement.webidl \
   HTMLBaseElement.webidl \
   HTMLBodyElement.webidl \
   HTMLBRElement.webidl \
   HTMLButtonElement.webidl \