ui: Allow individual test suites to opt-out of the TestCompositor.

ui/gl/gl_gl_api_implementation.cc

Index: ui/gl/gl_gl_api_implementation.cc
diff --git a/ui/gl/gl_gl_api_implementation.cc b/ui/gl/gl_gl_api_implementation.cc
index 2b7a5907e1e853a5556ccb7ecfe59710d478a604..f925f64ffa88af185c41ca880c09a484e094706d 100644
--- a/ui/gl/gl_gl_api_implementation.cc
+++ b/ui/gl/gl_gl_api_implementation.cc
@@ -237,6 +237,11 @@ void DriverGL::InitializeNullDrawBindings() {
   null_draw_bindings_enabled = true;
 }
 
+bool DriverGL::HasInitializedNullDrawBindings() {
+  return orig_fn.glClearFn != NULL && orig_fn.glDrawArraysFn != NULL &&
+         orig_fn.glDrawElementsFn != NULL;
+}
+
 bool DriverGL::SetNullDrawBindingsEnabled(bool enabled) {
   DCHECK(orig_fn.glClearFn != NULL);
   DCHECK(orig_fn.glDrawArraysFn != NULL);
@@ -290,6 +295,10 @@ void InitializeNullDrawGLBindingsGL() {
   g_driver_gl.InitializeNullDrawBindings();
 }
 
+bool HasInitializedNullDrawGLBindingsGL() {
+  return g_driver_gl.HasInitializedNullDrawBindings();
+}
+
 bool SetNullDrawGLBindingsEnabledGL(bool enabled) {
   return g_driver_gl.SetNullDrawBindingsEnabled(enabled);
 }