diff -r 000000000000 -r 6474c204b198 parser/html/nsHtml5TreeOpStage.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser/html/nsHtml5TreeOpStage.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,74 @@
+/* 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 "nsHtml5TreeOpStage.h"
+
+nsHtml5TreeOpStage::nsHtml5TreeOpStage()
+ : mMutex("nsHtml5TreeOpStage mutex")
+{
+}
+    
+nsHtml5TreeOpStage::~nsHtml5TreeOpStage()
+{
+}
+
+void
+nsHtml5TreeOpStage::MoveOpsFrom(nsTArray<nsHtml5TreeOperation>& aOpQueue)
+{
+  mozilla::MutexAutoLock autoLock(mMutex);
+  if (mOpQueue.IsEmpty()) {
+    mOpQueue.SwapElements(aOpQueue);
+  } else {
+    mOpQueue.MoveElementsFrom(aOpQueue);
+  }
+}
+    
+void
+nsHtml5TreeOpStage::MoveOpsAndSpeculativeLoadsTo(nsTArray<nsHtml5TreeOperation>& aOpQueue,
+    nsTArray<nsHtml5SpeculativeLoad>& aSpeculativeLoadQueue)
+{
+  mozilla::MutexAutoLock autoLock(mMutex);
+  if (aOpQueue.IsEmpty()) {
+    mOpQueue.SwapElements(aOpQueue);
+  } else {
+    aOpQueue.MoveElementsFrom(mOpQueue);
+  }
+  if (aSpeculativeLoadQueue.IsEmpty()) {
+    mSpeculativeLoadQueue.SwapElements(aSpeculativeLoadQueue);
+  } else {
+    aSpeculativeLoadQueue.MoveElementsFrom(mSpeculativeLoadQueue);
+  }
+}
+
+void
+nsHtml5TreeOpStage::MoveSpeculativeLoadsFrom(nsTArray<nsHtml5SpeculativeLoad>& aSpeculativeLoadQueue)
+{
+  mozilla::MutexAutoLock autoLock(mMutex);
+  if (mSpeculativeLoadQueue.IsEmpty()) {
+    mSpeculativeLoadQueue.SwapElements(aSpeculativeLoadQueue);
+  } else {
+    mSpeculativeLoadQueue.MoveElementsFrom(aSpeculativeLoadQueue);
+  }
+}
+
+void
+nsHtml5TreeOpStage::MoveSpeculativeLoadsTo(nsTArray<nsHtml5SpeculativeLoad>& aSpeculativeLoadQueue)
+{
+  mozilla::MutexAutoLock autoLock(mMutex);
+  if (aSpeculativeLoadQueue.IsEmpty()) {
+    mSpeculativeLoadQueue.SwapElements(aSpeculativeLoadQueue);
+  } else {
+    aSpeculativeLoadQueue.MoveElementsFrom(mSpeculativeLoadQueue);
+  }
+}
+
+#ifdef DEBUG
+void
+nsHtml5TreeOpStage::AssertEmpty()
+{
+  mozilla::MutexAutoLock autoLock(mMutex);
+  // This shouldn't really need the mutex
+  NS_ASSERTION(mOpQueue.IsEmpty(), "The stage was supposed to be empty.");
+}
+#endif