Temporarily adds another constructor to Compositor

ui/compositor/test/context_factories_for_test.cc

Index: ui/compositor/test/context_factories_for_test.cc
diff --git a/ui/compositor/test/context_factories_for_test.cc b/ui/compositor/test/context_factories_for_test.cc
index 045739d0a6551f8decb447b81569c2b6ea1a045d..dbee78cf4e98e8b213f2303a40ec8e3693f657ad 100644
--- a/ui/compositor/test/context_factories_for_test.cc
+++ b/ui/compositor/test/context_factories_for_test.cc
@@ -21,7 +21,7 @@ static gfx::DisableNullDrawGLBindings* g_disable_null_draw = NULL;
 namespace ui {
 
 // static
-void InitializeContextFactoryForTests(bool enable_pixel_output) {
+ui::ContextFactory* InitializeContextFactoryForTests(bool enable_pixel_output) {
   DCHECK(!g_implicit_factory) <<
       "ContextFactory for tests already initialized.";
   CommandLine* command_line = CommandLine::ForCurrentProcess();
@@ -31,6 +31,7 @@ void InitializeContextFactoryForTests(bool enable_pixel_output) {
     g_disable_null_draw = new gfx::DisableNullDrawGLBindings;
   g_implicit_factory = new InProcessContextFactory();
   ContextFactory::SetInstance(g_implicit_factory);
+  return g_implicit_factory;
 }
 
 void TerminateContextFactoryForTests() {