From 94053b9a07283c4aaed1ac51fb1724d7dfa6a909 Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@mozilla.com>
Date: Wed, 18 Sep 2013 17:17:02 -0700
Subject: [PATCH] Force composition on expose events (bug 915809,
 r=mattwoodrow).

---
 widget/gtk2/nsWindow.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/widget/gtk2/nsWindow.cpp b/widget/gtk2/nsWindow.cpp
index d8545cdc557..1e24d759347 100644
--- a/widget/gtk2/nsWindow.cpp
+++ b/widget/gtk2/nsWindow.cpp
@@ -105,6 +105,7 @@ extern "C" {
 #include "LayerManagerOGL.h"
 #include "GLContextProvider.h"
 #include "mozilla/gfx/2D.h"
+#include "mozilla/layers/CompositorParent.h"
 
 #ifdef MOZ_X11
 #include "gfxXlibSurface.h"
@@ -1975,6 +1976,12 @@ nsWindow::OnExposeEvent(cairo_t *cr)
     if (!listener)
         return FALSE;
 
+    // Do an early async composite so that we at least have something on screen
+    // in the right place, even if the content is out of date.
+    if (GetLayerManager()->GetBackendType() == LAYERS_CLIENT && mCompositorParent) {
+        mCompositorParent->ScheduleRenderOnCompositorThread();
+    }
+
     // Dispatch WillPaintWindow notification to allow scripts etc. to run
     // before we paint
     {