diff -r 000000000000 -r 6474c204b198 content/base/src/mozAutoDocUpdate.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/src/mozAutoDocUpdate.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,89 @@
+/* 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 mozAutoDocUpdate_h_
+#define mozAutoDocUpdate_h_
+
+#include "nsContentUtils.h" // For AddScriptBlocker() and RemoveScriptBlocker().
+#include "nsIDocument.h"
+#include "nsIDocumentObserver.h"
+
+/**
+ * Helper class to automatically handle batching of document updates.  This
+ * class will call BeginUpdate on construction and EndUpdate on destruction on
+ * the given document with the given update type.  The document could be null,
+ * in which case no updates will be called.  The constructor also takes a
+ * boolean that can be set to false to prevent notifications.
+ */
+class MOZ_STACK_CLASS mozAutoDocUpdate
+{
+public:
+  mozAutoDocUpdate(nsIDocument* aDocument, nsUpdateType aUpdateType,
+                   bool aNotify) :
+    mDocument(aNotify ? aDocument : nullptr),
+    mUpdateType(aUpdateType)
+  {
+    if (mDocument) {
+      mDocument->BeginUpdate(mUpdateType);
+    }
+    else {
+      nsContentUtils::AddScriptBlocker();
+    }
+  }
+
+  ~mozAutoDocUpdate()
+  {
+    if (mDocument) {
+      mDocument->EndUpdate(mUpdateType);
+    }
+    else {
+      nsContentUtils::RemoveScriptBlocker();
+    }
+  }
+
+private:
+  nsCOMPtr<nsIDocument> mDocument;
+  nsUpdateType mUpdateType;
+};
+
+#define MOZ_AUTO_DOC_UPDATE_PASTE2(tok,line) tok##line
+#define MOZ_AUTO_DOC_UPDATE_PASTE(tok,line) \
+  MOZ_AUTO_DOC_UPDATE_PASTE2(tok,line)
+#define MOZ_AUTO_DOC_UPDATE(doc,type,notify) \
+  mozAutoDocUpdate MOZ_AUTO_DOC_UPDATE_PASTE(_autoDocUpdater_, __LINE__) \
+  (doc,type,notify)
+
+
+/**
+ * Creates an update batch only under certain conditions.
+ * Use this rather than mozAutoDocUpdate when you expect inner updates
+ * to notify but you don't always want to spec cycles creating a batch.
+ * This is needed to avoid having this batch always create a blocker,
+ * but then have inner mozAutoDocUpdate call the last EndUpdate before.
+ * we remove that blocker. See bug 423269.
+ */
+class MOZ_STACK_CLASS mozAutoDocConditionalContentUpdateBatch
+{
+public:
+  mozAutoDocConditionalContentUpdateBatch(nsIDocument* aDocument,
+                                          bool aNotify) :
+    mDocument(aNotify ? aDocument : nullptr)
+  {
+    if (mDocument) {
+      mDocument->BeginUpdate(UPDATE_CONTENT_MODEL);
+    }
+  }
+
+  ~mozAutoDocConditionalContentUpdateBatch()
+  {
+    if (mDocument) {
+      mDocument->EndUpdate(UPDATE_CONTENT_MODEL);
+    }
+  }
+
+private:
+  nsCOMPtr<nsIDocument> mDocument;
+};
+
+#endif