diff -r 000000000000 -r 6474c204b198 layout/inspector/nsFontFaceList.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/inspector/nsFontFaceList.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,95 @@
+/* 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 "nsFontFaceList.h"
+#include "nsFontFace.h"
+#include "nsFontFaceLoader.h"
+#include "nsIFrame.h"
+#include "gfxFont.h"
+#include "mozilla/gfx/2D.h"
+
+nsFontFaceList::nsFontFaceList()
+{
+}
+
+nsFontFaceList::~nsFontFaceList()
+{
+}
+
+////////////////////////////////////////////////////////////////////////
+// nsISupports
+
+NS_IMPL_ISUPPORTS(nsFontFaceList, nsIDOMFontFaceList)
+
+////////////////////////////////////////////////////////////////////////
+// nsIDOMFontFaceList
+
+/* nsIDOMFontFace item (in unsigned long index); */
+struct FindByIndexData {
+  uint32_t mTarget;
+  uint32_t mCurrent;
+  nsIDOMFontFace* mResult;
+};
+
+static PLDHashOperator
+FindByIndex(gfxFontEntry* aKey, nsIDOMFontFace* aData, void* aUserData)
+{
+  FindByIndexData* data = static_cast<FindByIndexData*>(aUserData);
+  if (data->mCurrent == data->mTarget) {
+    data->mResult = aData;
+    return PL_DHASH_STOP;
+  }
+  data->mCurrent++;
+  return PL_DHASH_NEXT;
+}
+
+NS_IMETHODIMP
+nsFontFaceList::Item(uint32_t index, nsIDOMFontFace **_retval)
+{
+  NS_ENSURE_TRUE(index < mFontFaces.Count(), NS_ERROR_INVALID_ARG);
+  FindByIndexData userData;
+  userData.mTarget = index;
+  userData.mCurrent = 0;
+  userData.mResult = nullptr;
+  mFontFaces.EnumerateRead(FindByIndex, &userData);
+  NS_ASSERTION(userData.mResult != nullptr, "null entry in nsFontFaceList?");
+  NS_IF_ADDREF(*_retval = userData.mResult);
+  return NS_OK;
+}
+
+/* readonly attribute unsigned long length; */
+NS_IMETHODIMP
+nsFontFaceList::GetLength(uint32_t *aLength)
+{
+  *aLength = mFontFaces.Count();
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////
+// nsFontFaceList
+
+nsresult
+nsFontFaceList::AddFontsFromTextRun(gfxTextRun* aTextRun,
+                                    uint32_t aOffset, uint32_t aLength)
+{
+  gfxTextRun::GlyphRunIterator iter(aTextRun, aOffset, aLength);
+  while (iter.NextRun()) {
+    gfxFontEntry *fe = iter.GetGlyphRun()->mFont->GetFontEntry();
+    // if we have already listed this face, just make sure the match type is
+    // recorded
+    nsFontFace* existingFace =
+      static_cast<nsFontFace*>(mFontFaces.GetWeak(fe));
+    if (existingFace) {
+      existingFace->AddMatchType(iter.GetGlyphRun()->mMatchType);
+    } else {
+      // A new font entry we haven't seen before
+      nsRefPtr<nsFontFace> ff =
+        new nsFontFace(fe, aTextRun->GetFontGroup(),
+                       iter.GetGlyphRun()->mMatchType);
+      mFontFaces.Put(fe, ff);
+    }
+  }
+
+  return NS_OK;
+}