Don't allow software fallback for UI compositor on CrOS

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 76e09c4566726506239bd77e6b9fecf25f84a40f..e334fc41a1599d032747d44dc0d60c57c1d3c491 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -514,6 +514,10 @@ void Compositor::Layout() {
 }
 
 scoped_ptr<cc::OutputSurface> Compositor::CreateOutputSurface(bool fallback) {
+  // Chrome OS doesn't support falling back to software.
+#if defined(OS_CHROMEOS)

[danakj, 2014/01/06 19:33:06]

Can we keep the #ifdefs out of ui::Compositor and do this in the transport
factory?

[ccameron, 2014/01/06 19:47:02]

Sure -- done!

+  fallback = false;
+#endif
   return ContextFactory::GetInstance()->CreateOutputSurface(this, fallback);
 }