diff -r 000000000000 -r 6474c204b198 gfx/layers/ipc/ShadowLayerUtilsX11.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/ipc/ShadowLayerUtilsX11.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,138 @@
+/* -*- 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 "ShadowLayerUtilsX11.h"
+#include <X11/X.h>                      // for Drawable, XID
+#include <X11/Xlib.h>                   // for Display, Visual, etc
+#include <X11/extensions/Xrender.h>     // for XRenderPictFormat, etc
+#include <X11/extensions/render.h>      // for PictFormat
+#include "cairo-xlib.h"
+#include <stdint.h>                     // for uint32_t
+#include "GLDefs.h"                     // for GLenum
+#include "gfxPlatform.h"                // for gfxPlatform
+#include "gfxXlibSurface.h"             // for gfxXlibSurface
+#include "gfx2DGlue.h"                  // for Moz2D transistion helpers
+#include "mozilla/X11Util.h"            // for DefaultXDisplay, FinishX, etc
+#include "mozilla/gfx/Point.h"          // for IntSize
+#include "mozilla/layers/CompositableForwarder.h"
+#include "mozilla/layers/CompositorTypes.h"  // for OpenMode
+#include "mozilla/layers/ISurfaceAllocator.h"  // for ISurfaceAllocator, etc
+#include "mozilla/layers/LayerManagerComposite.h"
+#include "mozilla/layers/LayersSurfaces.h"  // for SurfaceDescriptor, etc
+#include "mozilla/layers/ShadowLayers.h"  // for ShadowLayerForwarder, etc
+#include "mozilla/mozalloc.h"           // for operator new
+#include "nsAutoPtr.h"                  // for nsRefPtr
+#include "nsCOMPtr.h"                   // for already_AddRefed
+#include "nsDebug.h"                    // for NS_ERROR
+#include "prenv.h"                      // for PR_GetEnv
+
+using namespace mozilla::gl;
+
+namespace mozilla {
+namespace gl {
+class GLContext;
+class TextureImage;
+}
+
+namespace layers {
+
+// Return true if we're likely compositing using X and so should use
+// Xlib surfaces in shadow layers.
+static bool
+UsingXCompositing()
+{
+  if (!PR_GetEnv("MOZ_LAYERS_ENABLE_XLIB_SURFACES")) {
+      return false;
+  }
+  return (gfxSurfaceType::Xlib ==
+          gfxPlatform::GetPlatform()->ScreenReferenceSurface()->GetType());
+}
+
+// LookReturn a pointer to |aFormat| that lives in the Xrender library.
+// All code using render formats assumes it doesn't need to copy.
+static XRenderPictFormat*
+GetXRenderPictFormatFromId(Display* aDisplay, PictFormat aFormatId)
+{
+  XRenderPictFormat tmplate;
+  tmplate.id = aFormatId;
+  return XRenderFindFormat(aDisplay, PictFormatID, &tmplate, 0);
+}
+
+SurfaceDescriptorX11::SurfaceDescriptorX11(gfxXlibSurface* aSurf)
+  : mId(aSurf->XDrawable())
+  , mSize(aSurf->GetSize().ToIntSize())
+{
+  const XRenderPictFormat *pictFormat = aSurf->XRenderFormat();
+  if (pictFormat) {
+    mFormat = pictFormat->id;
+  } else {
+    mFormat = cairo_xlib_surface_get_visual(aSurf->CairoSurface())->visualid;
+  }
+}
+
+SurfaceDescriptorX11::SurfaceDescriptorX11(Drawable aDrawable, XID aFormatID,
+                                           const gfx::IntSize& aSize)
+  : mId(aDrawable)
+  , mFormat(aFormatID)
+  , mSize(aSize)
+{ }
+
+already_AddRefed<gfxXlibSurface>
+SurfaceDescriptorX11::OpenForeign() const
+{
+  Display* display = DefaultXDisplay();
+  Screen* screen = DefaultScreenOfDisplay(display);
+
+  nsRefPtr<gfxXlibSurface> surf;
+  XRenderPictFormat* pictFormat = GetXRenderPictFormatFromId(display, mFormat);
+  if (pictFormat) {
+    surf = new gfxXlibSurface(screen, mId, pictFormat, gfx::ThebesIntSize(mSize));
+  } else {
+    Visual* visual;
+    int depth;
+    FindVisualAndDepth(display, mFormat, &visual, &depth);
+    if (!visual)
+      return nullptr;
+
+    surf = new gfxXlibSurface(display, mId, visual, gfx::ThebesIntSize(mSize));
+  }
+  return surf->CairoStatus() ? nullptr : surf.forget();
+}
+
+/*static*/ void
+ShadowLayerForwarder::PlatformSyncBeforeUpdate()
+{
+  if (UsingXCompositing()) {
+    // If we're using X surfaces, then we need to finish all pending
+    // operations on the back buffers before handing them to the
+    // parent, otherwise the surface might be used by the parent's
+    // Display in between two operations queued by our Display.
+    FinishX(DefaultXDisplay());
+  }
+}
+
+/*static*/ void
+LayerManagerComposite::PlatformSyncBeforeReplyUpdate()
+{
+  if (UsingXCompositing()) {
+    // If we're using X surfaces, we need to finish all pending
+    // operations on the *front buffers* before handing them back to
+    // the child, even though they will be read operations.
+    // Otherwise, the child might start scribbling on new back buffers
+    // that are still participating in requests as old front buffers.
+    FinishX(DefaultXDisplay());
+  }
+}
+
+/*static*/ bool
+LayerManagerComposite::SupportsDirectTexturing()
+{
+  return false;
+}
+
+} // namespace layers
+} // namespace mozilla