Don't register classes only found at runtime

Summary:
This caused issues for me when I tried to provide a native module on init that was also KVO'd (and dynamically subclassed)

On closer inspection, it also seems highly inconsistent to register these classes in DEBUG mode but have them fail silently in production. Reducing the difference between debug and release seems like a safer option.

public

Reviewed By: nicklockwood

Differential Revision: D2819838

fb-gh-sync-id: 79ab72b1152c89eae38c965ff7724aba59a00949

React/Base/RCTBridge.m

@@ -57,6 +57,9 @@ void RCTRegisterModule(Class moduleClass)
 
   // Register module
   [RCTModuleClasses addObject:moduleClass];
+
+  objc_setAssociatedObject(moduleClass, &RCTBridgeModuleClassIsRegistered,
+                           @NO, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }
 
 /**
@@ -118,10 +121,6 @@ + (void)initialize
           if (![RCTModuleClasses containsObject:cls]) {
             RCTLogWarn(@"Class %@ was not exported. Did you forget to use "
                        "RCT_EXPORT_MODULE()?", cls);
-
-            RCTRegisterModule(cls);
-            objc_setAssociatedObject(cls, &RCTBridgeModuleClassIsRegistered,
-                                     @NO, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
           }
           break;
         }