diff -r 000000000000 -r 6474c204b198 content/canvas/src/WebGLQuery.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/WebGLQuery.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "WebGLContext.h"
+#include "GLContext.h"
+#include "WebGLQuery.h"
+#include "mozilla/dom/WebGL2RenderingContextBinding.h"
+#include "nsContentUtils.h"
+
+using namespace mozilla;
+
+JSObject*
+WebGLQuery::WrapObject(JSContext *cx) {
+    return dom::WebGLQueryBinding::Wrap(cx, this);
+}
+
+WebGLQuery::WebGLQuery(WebGLContext* context)
+    : WebGLContextBoundObject(context)
+    , mGLName(0)
+    , mType(0)
+{
+    SetIsDOMBinding();
+    mContext->mQueries.insertBack(this);
+
+    mContext->MakeContextCurrent();
+    mContext->gl->fGenQueries(1, &mGLName);
+}
+
+void WebGLQuery::Delete() {
+    mContext->MakeContextCurrent();
+    mContext->gl->fDeleteQueries(1, &mGLName);
+    LinkedListElement<WebGLQuery>::removeFrom(mContext->mQueries);
+}
+
+bool WebGLQuery::IsActive() const
+{
+    WebGLRefPtr<WebGLQuery>* targetSlot = mContext->GetQueryTargetSlot(mType, "WebGLQuery::IsActive()");
+
+    MOZ_ASSERT(targetSlot, "unknown query object's type");
+
+    return targetSlot && *targetSlot == this;
+}
+
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(WebGLQuery)
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(WebGLQuery, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(WebGLQuery, Release)