Log the performer name in the ConsoleLoggingTracer, not the object it…

…self.

Reviewers: O4 Material Motion Apple platform reviewers, O2 Material Motion, markwei

Reviewed By: O4 Material Motion Apple platform reviewers, O2 Material Motion, markwei

Tags: #material_motion

Differential Revision: http://codereview.cc/D1922

src/MDMConsoleLoggingTracer.m

@@ -71,8 +71,8 @@ - (void)didRemovePlanNamed:(NSString *)name from:(id)target {
   NSLog(@"didRemovePlan named %@ from target: %@\n\n", name, target);
 }
 
-- (void)didCreatePerformer:(id<MDMPerforming>)performer for:(id)target {
-  NSLog(@"didCreatePerformer: %@ for: %@\n\n", performer, target);
+- (void)didCreatePerformer:(NSObject<MDMPerforming> *)performer for:(id)target {
+  NSLog(@"didCreatePerformer: %@ for: %@\n\n", NSStringFromClass([performer class]), target);
 }
 
 @end