diff -r 000000000000 -r 6474c204b198 gfx/layers/ipc/FenceUtilsGonk.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/ipc/FenceUtilsGonk.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,123 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* 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 "GLContext.h"
+#include "mozilla/unused.h"
+#include "nsXULAppAPI.h"
+
+#include "FenceUtilsGonk.h"
+
+using namespace android;
+using namespace base;
+using namespace mozilla::layers;
+
+namespace IPC {
+
+void
+ParamTraits<FenceHandle>::Write(Message* aMsg,
+                                const paramType& aParam)
+{
+#if ANDROID_VERSION >= 19
+  sp<Fence> flattenable = aParam.mFence;
+#else
+  Flattenable *flattenable = aParam.mFence.get();
+#endif
+  size_t nbytes = flattenable->getFlattenedSize();
+  size_t nfds = flattenable->getFdCount();
+
+  char data[nbytes];
+  int fds[nfds];
+
+#if ANDROID_VERSION >= 19
+  // Make a copy of "data" and "fds" for flatten() to avoid casting problem
+  void *pdata = (void *)data;
+  int *pfds = fds;
+
+  flattenable->flatten(pdata, nbytes, pfds, nfds);
+
+  // In Kitkat, flatten() will change the value of nbytes and nfds, which dues
+  // to multiple parcelable object consumption. The actual size and fd count
+  // which returned by getFlattenedSize() and getFdCount() are not changed.
+  // So we change nbytes and nfds back by call corresponding calls.
+  nbytes = flattenable->getFlattenedSize();
+  nfds = flattenable->getFdCount();
+#else
+  flattenable->flatten(data, nbytes, fds, nfds);
+#endif
+  aMsg->WriteSize(nbytes);
+  aMsg->WriteSize(nfds);
+
+  aMsg->WriteBytes(data, nbytes);
+  for (size_t n = 0; n < nfds; ++n) {
+    // These buffers can't die in transit because they're created
+    // synchonously and the parent-side buffer can only be dropped if
+    // there's a crash.
+    aMsg->WriteFileDescriptor(FileDescriptor(fds[n], false));
+  }
+}
+
+bool
+ParamTraits<FenceHandle>::Read(const Message* aMsg,
+                               void** aIter, paramType* aResult)
+{
+  size_t nbytes;
+  size_t nfds;
+  const char* data;
+
+  if (!aMsg->ReadSize(aIter, &nbytes) ||
+      !aMsg->ReadSize(aIter, &nfds) ||
+      !aMsg->ReadBytes(aIter, &data, nbytes)) {
+    return false;
+  }
+
+  int fds[nfds];
+
+  for (size_t n = 0; n < nfds; ++n) {
+    FileDescriptor fd;
+    if (!aMsg->ReadFileDescriptor(aIter, &fd)) {
+      return false;
+    }
+    // If the GraphicBuffer was shared cross-process, SCM_RIGHTS does
+    // the right thing and dup's the fd.  If it's shared cross-thread,
+    // SCM_RIGHTS doesn't dup the fd.  That's surprising, but we just
+    // deal with it here.  NB: only the "default" (master) process can
+    // alloc gralloc buffers.
+    bool sameProcess = (XRE_GetProcessType() == GeckoProcessType_Default);
+    int dupFd = sameProcess ? dup(fd.fd) : fd.fd;
+    fds[n] = dupFd;
+  }
+
+  sp<Fence> buffer(new Fence());
+#if ANDROID_VERSION >= 19
+  // Make a copy of "data" and "fds" for unflatten() to avoid casting problem
+  void const *pdata = (void const *)data;
+  int const *pfds = fds;
+
+  if (NO_ERROR == buffer->unflatten(pdata, nbytes, pfds, nfds)) {
+#else
+  Flattenable *flattenable = buffer.get();
+
+  if (NO_ERROR == flattenable->unflatten(data, nbytes, fds, nfds)) {
+#endif
+    aResult->mFence = buffer;
+    return true;
+  }
+  return false;
+}
+
+} // namespace IPC
+
+namespace mozilla {
+namespace layers {
+
+FenceHandle::FenceHandle(const sp<Fence>& aFence)
+  : mFence(aFence)
+{
+}
+
+} // namespace layers
+} // namespace mozilla