diff -r 000000000000 -r 6474c204b198 layout/tools/layout-debug/src/nsRegressionTester.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/tools/layout-debug/src/nsRegressionTester.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,151 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsISupports.h"
+#include "nsRegressionTester.h"
+
+#include "nsXPIDLString.h"
+#include "nsReadableUtils.h"
+#include "nsIWindowWatcher.h"
+#include "nsPIDOMWindow.h"
+#include "nsIPresShell.h"
+#include "nsIURI.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIDocShell.h"
+#include "nsIContentViewer.h"
+#include "nsIContentViewerFile.h"
+#include "nsIFrame.h"
+#include "nsStyleStruct.h"
+#include "nsIFrameUtil.h"
+#include "nsLayoutCID.h"
+#include "nsNetUtil.h"
+#include "nsIFile.h"
+#include "nsViewManager.h"
+#include "nsView.h"
+
+
+
+static NS_DEFINE_CID(kFrameUtilCID, NS_FRAME_UTIL_CID);
+
+
+nsRegressionTester::nsRegressionTester()
+{
+}
+
+nsRegressionTester::~nsRegressionTester() 
+{
+}
+
+NS_IMPL_ISUPPORTS(nsRegressionTester, nsILayoutRegressionTester)
+
+NS_IMETHODIMP
+nsRegressionTester::DumpFrameModel(nsIDOMWindow *aWindowToDump,
+                                   nsIFile *aDestFile,
+                                   uint32_t aFlagsMask, int32_t *aResult)
+{
+  NS_ENSURE_ARG(aWindowToDump);
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  *aResult = DUMP_RESULT_ERROR;
+
+#ifndef DEBUG
+  return NS_ERROR_NOT_AVAILABLE;
+#else
+  nsresult    rv = NS_ERROR_NOT_AVAILABLE;
+  uint32_t    busyFlags;
+  bool        stillLoading;
+
+  nsCOMPtr<nsIDocShell> docShell;
+  rv = GetDocShellFromWindow(aWindowToDump, getter_AddRefs(docShell));
+  if (NS_FAILED(rv)) return rv;
+
+  // find out if the document is loaded
+  docShell->GetBusyFlags(&busyFlags);
+  stillLoading = busyFlags & (nsIDocShell::BUSY_FLAGS_BUSY |
+                              nsIDocShell::BUSY_FLAGS_PAGE_LOADING);
+  if (stillLoading)
+  {
+    *aResult = DUMP_RESULT_LOADING;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
+
+  nsIFrame* root = presShell->GetRootFrame();
+
+  FILE* fp = stdout;
+  if (aDestFile)
+  {
+    rv = aDestFile->OpenANSIFileDesc("w", &fp);
+    if (NS_FAILED(rv)) return rv;
+  }
+  if (aFlagsMask & DUMP_FLAGS_MASK_PRINT_MODE) {
+    nsCOMPtr <nsIContentViewer> viewer;
+    docShell->GetContentViewer(getter_AddRefs(viewer));
+    if (viewer){
+      nsCOMPtr<nsIContentViewerFile> viewerFile = do_QueryInterface(viewer);
+      if (viewerFile) {
+         viewerFile->Print(true, fp, nullptr);
+      }
+    }
+  }
+  else {
+    root->DumpRegressionData(presShell->GetPresContext(), fp, 0);
+  }
+  if (fp != stdout)
+    fclose(fp);
+  *aResult = DUMP_RESULT_COMPLETED;
+  return NS_OK;
+#endif
+}
+
+NS_IMETHODIMP
+nsRegressionTester::CompareFrameModels(nsIFile *aBaseFile, nsIFile *aVerFile,
+                                       uint32_t aFlags, bool *aResult)
+{
+  NS_ENSURE_ARG(aBaseFile);
+  NS_ENSURE_ARG(aVerFile);
+  NS_ENSURE_ARG_POINTER(aResult);
+  
+  *aResult = false;
+  
+  nsresult rv;
+  FILE* baseFile;
+  rv = aBaseFile->OpenANSIFileDesc("r", &baseFile);
+  if (NS_FAILED(rv)) return rv;
+
+  FILE* verFile;
+  rv = aVerFile->OpenANSIFileDesc("r", &verFile);
+  if (NS_FAILED(rv)) {
+    fclose(baseFile);
+    return rv;
+  }
+
+  nsCOMPtr<nsIFrameUtil> frameUtil = do_CreateInstance(kFrameUtilCID, &rv);
+  if (NS_SUCCEEDED(rv))
+  {
+    int32_t outputLevel = (aFlags == COMPARE_FLAGS_VERBOSE) ? 0 : 1;
+    rv = frameUtil->CompareRegressionData(baseFile, verFile, outputLevel);
+    // CompareRegressionData closes |baseFile| and |verFile|.
+  } else {
+    fclose(verFile);          
+    fclose(baseFile);
+  }
+
+  *aResult = NS_FAILED(rv);
+  return NS_OK;
+}
+
+nsresult
+nsRegressionTester::GetDocShellFromWindow(nsIDOMWindow* inWindow, nsIDocShell** outShell)
+{
+  nsCOMPtr<nsPIDOMWindow> window(do_QueryInterface(inWindow));
+  if (!window) return NS_ERROR_FAILURE;
+
+  *outShell = window->GetDocShell();
+  NS_IF_ADDREF(*outShell);
+
+  return NS_OK;
+}