diff --git a/dom/base/WindowNamedPropertiesHandler.cpp b/dom/base/WindowNamedPropertiesHandler.cpp
index 4ed4655bbe61..8c564bbd9823 100644
--- a/dom/base/WindowNamedPropertiesHandler.cpp
+++ b/dom/base/WindowNamedPropertiesHandler.cpp
@@ -8,7 +8,6 @@
 #include "mozilla/dom/EventTargetBinding.h"
 #include "mozilla/dom/WindowBinding.h"
 #include "nsContentUtils.h"
-#include "nsDOMClassInfo.h"
 #include "nsDOMWindowList.h"
 #include "nsGlobalWindow.h"
 #include "nsHTMLDocument.h"
diff --git a/dom/base/moz.build b/dom/base/moz.build
index 81dd8e2019c8..c19d67789bc3 100644
--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -295,7 +295,6 @@ UNIFIED_SOURCES += [
     'nsDocumentEncoder.cpp',
     'nsDOMAttributeMap.cpp',
     'nsDOMCaretPosition.cpp',
-    'nsDOMClassInfo.cpp',
     'nsDOMMutationObserver.cpp',
     'nsDOMNavigationTiming.cpp',
     'nsDOMSerializer.cpp',
diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
deleted file mode 100644
index 4847c68ea83d..000000000000
--- a/dom/base/nsDOMClassInfo.cpp
+++ /dev/null
@@ -1,109 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* 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 "mozilla/ArrayUtils.h"
-
-// JavaScript includes
-#include "jsapi.h"
-#include "jsfriendapi.h"
-#include "WrapperFactory.h"
-#include "AccessCheck.h"
-#include "XrayWrapper.h"
-
-#include "xpcpublic.h"
-#include "xpcprivate.h"
-#include "xpc_make_class.h"
-#include "XPCWrapper.h"
-
-#include "mozilla/DOMEventTargetHelper.h"
-#include "mozilla/dom/RegisterBindings.h"
-
-#include "nscore.h"
-#include "nsDOMClassInfo.h"
-#include "nsIDOMClassInfo.h"
-#include "nsCRT.h"
-#include "nsCRTGlue.h"
-#include "nsICategoryManager.h"
-#include "nsIComponentRegistrar.h"
-#include "nsXPCOM.h"
-#include "nsISimpleEnumerator.h"
-#include "nsISupportsPrimitives.h"
-#include "nsIXPConnect.h"
-#include "xptcall.h"
-#include "nsTArray.h"
-
-// General helper includes
-#include "nsGlobalWindow.h"
-#include "nsIContent.h"
-#include "nsIDocument.h"
-#include "nsIDOMDocument.h"
-#include "nsIDOMEvent.h"
-#include "nsIDOMEventListener.h"
-#include "nsContentUtils.h"
-#include "nsIDOMGlobalPropertyInitializer.h"
-#include "mozilla/Attributes.h"
-#include "mozilla/Telemetry.h"
-
-// DOM base includes
-#include "nsIDOMWindow.h"
-#include "nsPIDOMWindow.h"
-
-// DOM core includes
-#include "nsError.h"
-
-// Event related includes
-#include "nsIDOMEventTarget.h"
-
-// CSS related includes
-#include "nsMemory.h"
-
-// includes needed for the prototype chain interfaces
-
-#include "nsIEventListenerService.h"
-
-#include "mozilla/dom/TouchEvent.h"
-
-#include "nsWrapperCacheInlines.h"
-#include "mozilla/dom/HTMLCollectionBinding.h"
-
-#include "nsDebug.h"
-
-#include "mozilla/dom/BindingUtils.h"
-#include "mozilla/Likely.h"
-#include "nsIInterfaceInfoManager.h"
-
-#ifdef MOZ_TIME_MANAGER
-#include "TimeManager.h"
-#endif
-
-using namespace mozilla;
-using namespace mozilla::dom;
-
-bool nsDOMClassInfo::sIsInitialized = false;
-
-// static
-nsresult
-nsDOMClassInfo::Init()
-{
-  /* Errors that can trigger early returns are done first,
-     otherwise nsDOMClassInfo is left in a half inited state. */
-  static_assert(sizeof(uintptr_t) == sizeof(void*),
-                "BAD! You'll need to adjust the size of uintptr_t to the "
-                "size of a pointer on your platform.");
-
-  NS_ENSURE_TRUE(!sIsInitialized, NS_ERROR_ALREADY_INITIALIZED);
-
-  sIsInitialized = true;
-
-  return NS_OK;
-}
-
-// static
-void
-nsDOMClassInfo::ShutDown()
-{
-  sIsInitialized = false;
-}
diff --git a/dom/base/nsDOMClassInfo.h b/dom/base/nsDOMClassInfo.h
deleted file mode 100644
index 98f99fc8f822..000000000000
--- a/dom/base/nsDOMClassInfo.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* 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 nsDOMClassInfo_h___
-#define nsDOMClassInfo_h___
-
-#include "mozilla/Attributes.h"
-#include "nsIXPCScriptable.h"
-#include "nsIScriptGlobalObject.h"
-#include "js/Class.h"
-#include "js/Id.h"
-#include "nsIXPConnect.h"
-
-class nsDOMClassInfo
-{
-public:
-  static nsresult Init();
-  static void ShutDown();
-
-protected:
-  static bool sIsInitialized;
-};
-
-#endif /* nsDOMClassInfo_h___ */
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index c6eddcd0a00a..ab8cf069f35e 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -47,7 +47,6 @@
 #include "nsIDocShellTreeItem.h"
 #include "nsCOMArray.h"
 #include "nsQueryObject.h"
-#include "nsDOMClassInfo.h"
 #include "mozilla/Services.h"
 #include "nsScreen.h"
 #include "ChildIterator.h"
diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index 9c2983e703eb..8e28f3e1dec1 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -70,7 +70,6 @@
 #include "nsIContentSecurityPolicy.h"
 #include "GeckoProfiler.h"
 #include "nsPluginFrame.h"
-#include "nsDOMClassInfo.h"
 #include "nsWrapperCacheInlines.h"
 #include "nsDOMJSUtils.h"
 
diff --git a/dom/bindings/BindingUtils.cpp b/dom/bindings/BindingUtils.cpp
index 803d9794be2f..458bd049962e 100644
--- a/dom/bindings/BindingUtils.cpp
+++ b/dom/bindings/BindingUtils.cpp
@@ -55,7 +55,6 @@
 #include "mozilla/dom/WorkerScope.h"
 #include "mozilla/dom/XrayExpandoClass.h"
 #include "mozilla/jsipc/CrossProcessObjectWrappers.h"
-#include "nsDOMClassInfo.h"
 #include "ipc/ErrorIPCUtils.h"
 #include "mozilla/UseCounter.h"
 #include "mozilla/dom/DocGroup.h"
@@ -3281,25 +3280,17 @@ CreateGlobalOptionsWithXPConnect::PostCreateGlobal(JSContext* aCx,
 
 static bool sRegisteredDOMNames = false;
 
-nsresult
+static void
 RegisterDOMNames()
 {
   if (sRegisteredDOMNames) {
-    return NS_OK;
+    return;
   }
 
   // Register new DOM bindings
   WebIDLGlobalNameHash::Init();
 
-  nsresult rv = nsDOMClassInfo::Init();
-  if (NS_FAILED(rv)) {
-    NS_ERROR("Could not initialize nsDOMClassInfo");
-    return rv;
-  }
-
   sRegisteredDOMNames = true;
-
-  return NS_OK;
 }
 
 /* static */
@@ -3307,10 +3298,7 @@ bool
 CreateGlobalOptions<nsGlobalWindowInner>::PostCreateGlobal(JSContext* aCx,
                                                            JS::Handle<JSObject*> aGlobal)
 {
-  nsresult rv = RegisterDOMNames();
-  if (NS_FAILED(rv)) {
-    return Throw(aCx, rv);
-  }
+  RegisterDOMNames();
 
   return CreateGlobalOptionsWithXPConnect::PostCreateGlobal(aCx, aGlobal);
 }
diff --git a/dom/bindings/BindingUtils.h b/dom/bindings/BindingUtils.h
index 83f417af23d5..1c0de8443a21 100644
--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -3126,9 +3126,6 @@ struct CreateGlobalOptions<nsGlobalWindowInner>
   static bool PostCreateGlobal(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
 };
 
-nsresult
-RegisterDOMNames();
-
 // The return value is true if we created and successfully performed our part of
 // the setup for the global, false otherwise.
 //
diff --git a/dom/bindings/DOMJSProxyHandler.cpp b/dom/bindings/DOMJSProxyHandler.cpp
index 7968fbda905a..0e014b47cf10 100644
--- a/dom/bindings/DOMJSProxyHandler.cpp
+++ b/dom/bindings/DOMJSProxyHandler.cpp
@@ -9,7 +9,6 @@
 #include "xpcprivate.h"
 #include "XPCWrapper.h"
 #include "WrapperFactory.h"
-#include "nsDOMClassInfo.h"
 #include "nsWrapperCacheInlines.h"
 #include "mozilla/dom/BindingUtils.h"
 
diff --git a/dom/html/nsHTMLDocument.cpp b/dom/html/nsHTMLDocument.cpp
index 5d12f8f451d2..9fef56f7a7d5 100644
--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -106,7 +106,6 @@
 #include "mozilla/dom/Selection.h"
 #include "nsCharsetSource.h"
 #include "nsIStringBundle.h"
-#include "nsDOMClassInfo.h"
 #include "nsFocusManager.h"
 #include "nsIFrame.h"
 #include "nsIContent.h"
diff --git a/dom/xbl/nsXBLBinding.cpp b/dom/xbl/nsXBLBinding.cpp
index 4de8a67da4b5..afcfd77b1fd7 100644
--- a/dom/xbl/nsXBLBinding.cpp
+++ b/dom/xbl/nsXBLBinding.cpp
@@ -49,10 +49,6 @@
 #include "nsNodeUtils.h"
 #include "nsJSUtils.h"
 
-// Nasty hack.  Maybe we could move some of the classinfo utility methods
-// (e.g. WrapNative) over to nsContentUtils?
-#include "nsDOMClassInfo.h"
-
 #include "mozilla/DeferredFinalize.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/ScriptSettings.h"
diff --git a/js/xpconnect/src/XPCComponents.cpp b/js/xpconnect/src/XPCComponents.cpp
index 7a1d2472a7a5..34cbca7dae15 100644
--- a/js/xpconnect/src/XPCComponents.cpp
+++ b/js/xpconnect/src/XPCComponents.cpp
@@ -32,7 +32,6 @@
 #include "mozilla/Scheduler.h"
 #include "nsZipArchive.h"
 #include "nsWindowMemoryReporter.h"
-#include "nsDOMClassInfo.h"
 #include "ShimInterfaceInfo.h"
 #include "nsIException.h"
 #include "nsIScriptError.h"
diff --git a/js/xpconnect/src/XPCRuntimeService.cpp b/js/xpconnect/src/XPCRuntimeService.cpp
index b82f9d684526..b3b8afe76f2e 100644
--- a/js/xpconnect/src/XPCRuntimeService.cpp
+++ b/js/xpconnect/src/XPCRuntimeService.cpp
@@ -8,7 +8,6 @@
 
 #include "nsContentUtils.h"
 #include "BackstagePass.h"
-#include "nsDOMClassInfo.h"
 #include "nsIPrincipal.h"
 #include "mozilla/dom/BindingUtils.h"
 
diff --git a/layout/build/nsLayoutStatics.cpp b/layout/build/nsLayoutStatics.cpp
index 144ec0346143..1f33f6f67def 100644
--- a/layout/build/nsLayoutStatics.cpp
+++ b/layout/build/nsLayoutStatics.cpp
@@ -25,7 +25,6 @@
 #include "nsCSSRendering.h"
 #include "nsGenericHTMLFrameElement.h"
 #include "mozilla/dom/Attr.h"
-#include "nsDOMClassInfo.h"
 #include "mozilla/EventListenerManager.h"
 #include "nsFrame.h"
 #include "nsGlobalWindow.h"
@@ -367,7 +366,6 @@ nsLayoutStatics::Shutdown()
   ShutdownJSEnvironment();
   nsGlobalWindowInner::ShutDown();
   nsGlobalWindowOuter::ShutDown();
-  nsDOMClassInfo::ShutDown();
   WebIDLGlobalNameHash::Shutdown();
   nsListControlFrame::Shutdown();
   nsXBLService::Shutdown();
diff --git a/storage/mozStorageAsyncStatement.cpp b/storage/mozStorageAsyncStatement.cpp
index 46b76d5e0b60..e94c0985a01a 100644
--- a/storage/mozStorageAsyncStatement.cpp
+++ b/storage/mozStorageAsyncStatement.cpp
@@ -23,7 +23,6 @@
 #include "mozStoragePrivateHelpers.h"
 #include "mozStorageStatementRow.h"
 #include "mozStorageStatement.h"
-#include "nsDOMClassInfo.h"
 
 #include "mozilla/Logging.h"
 
diff --git a/storage/mozStorageStatement.cpp b/storage/mozStorageStatement.cpp
index 9552b0cc6776..ca812e45616a 100644
--- a/storage/mozStorageStatement.cpp
+++ b/storage/mozStorageStatement.cpp
@@ -23,7 +23,6 @@
 #include "mozStorageStatementRow.h"
 #include "mozStorageStatement.h"
 #include "GeckoProfiler.h"
-#include "nsDOMClassInfo.h"
 
 #include "mozilla/Logging.h"
 #include "mozilla/Printf.h"