Access singletons with a new GetInstance() method instead of Singleton<T>.

app/surface/io_surface_support_mac.cc

Index: app/surface/io_surface_support_mac.cc
diff --git a/app/surface/io_surface_support_mac.cc b/app/surface/io_surface_support_mac.cc
index 154f895b6e650c5b9ab0240921287ae7d8521d40..b27a5448ab93bbeb2879759f0868536a122d008e 100644
--- a/app/surface/io_surface_support_mac.cc
+++ b/app/surface/io_surface_support_mac.cc
@@ -80,10 +80,8 @@ class IOSurfaceSupportImpl : public IOSurfaceSupport {
   DISALLOW_COPY_AND_ASSIGN(IOSurfaceSupportImpl);
 };
 
-static Singleton<IOSurfaceSupportImpl> sole_instance_;
-
 IOSurfaceSupportImpl* IOSurfaceSupportImpl::Initialize() {
-  IOSurfaceSupportImpl* impl = sole_instance_.get();
+  IOSurfaceSupportImpl* impl = Singleton<IOSurfaceSupportImpl>::get();
   if (impl->InitializedSuccessfully())
     return impl;
   return NULL;