Way to register RCT_MODULE in Plugin2.0 instead of +load

Summary:
[RFC] WIP: Way to register RCT_MODULE in Plugin2.0 instead of +load

This seemed like the simplest way to do this to register in the existing
didNotFindModule callback so that we don't have to touch any opensource code.

NOTE: The new version of this fixes the problems with dylibs, but not the -ObjC flag removal. This seems like the right call to avoid users having to implement c-functions to return their classes; instead we used objc_getClass.

Reviewed By: dshahidehpour

Differential Revision: D9112719

fbshipit-source-id: cf8df97d7c443cafa0e06a1e61bdf2612944ed87

React/Base/RCTBridge+Private.h

@@ -21,6 +21,8 @@ RCT_EXTERN __attribute__((weak)) void RCTFBQuickPerformanceLoggerConfigureHooks(
 RCT_EXTERN void RCTVerifyAllModulesExported(NSArray *extraModules);
 #endif
 
+RCT_EXTERN void RCTRegisterModule(Class);
+
 @interface RCTBridge ()
 
 // Private designated initializer

React/Base/RCTBridgeModule.h

@@ -73,6 +73,16 @@ RCT_EXTERN void RCTRegisterModule(Class); \
 + (NSString *)moduleName { return @#js_name; } \
 + (void)load { RCTRegisterModule(self); }
 
+/**
+ * To improve startup performance users may want to generate their module lists
+ * at build time and hook the delegate to merge with the runtime list. This
+ * macro takes the place of the above for those cases by omitting the +load
+ * generation.
+ *
+ */
+#define RCT_EXPORT_PRE_REGISTERED_MODULE(js_name) \
++ (NSString *)moduleName { return @#js_name; }
+
 // Implemented by RCT_EXPORT_MODULE
 + (NSString *)moduleName;
 

React/CxxBridge/RCTCxxBridge.mm

@@ -650,19 +650,17 @@ - (void)installExtraJSBinding
   // Set up moduleData for automatically-exported modules
   NSArray<RCTModuleData *> *moduleDataById = [self registerModulesForClasses:modules];
 
-#ifdef RCT_DEBUG
   if (lazilyDiscovered) {
+#ifdef RCT_DEBUG
     // Lazily discovered modules do not require instantiation here,
     // as they are not allowed to have pre-instantiated instance
     // and must not require the main queue.
     for (RCTModuleData *moduleData in moduleDataById) {
       RCTAssert(!(moduleData.requiresMainQueueSetup || moduleData.hasInstance),
         @"Module \'%@\' requires initialization on the Main Queue or has pre-instantiated, which is not supported for the lazily discovered modules.", moduleData.name);
     }
-  }
-  else
 #endif
-  {
+  } else {
     RCT_PROFILE_BEGIN_EVENT(RCTProfileTagAlways,
                             @"-[RCTCxxBridge initModulesWithDispatchGroup:] moduleData.hasInstance", nil);
     // Dispatch module init onto main thread for those modules that require it