Export native commands codegen classes and fix build issue

Summary:
1. Generated `RCTComponentViewHelpers.h` file was not being exported.
2. argument declaration was within `if RCT_DEBUG` directive which meant in production it was stripped.

changelog: [internal]

Reviewed By: TheSavior

Differential Revision: D18266846

fbshipit-source-id: 4c13b8ee9cf4cb3b7486ba7cfef0c64bc46b2360

packages/react-native-codegen/DEFS.bzl

@@ -189,6 +189,7 @@ def rn_codegen_components(
             "ComponentDescriptors.h": ":{}".format(generate_component_descriptor_h_name),
             "EventEmitters.h": ":{}".format(generate_event_emitter_h_name),
             "Props.h": ":{}".format(generate_props_h_name),
+            "RCTComponentViewHelpers.h": ":{}".format(generate_component_hobjcpp_name),
             "ShadowNodes.h": ":{}".format(generate_shadow_node_h_name),
         },
         ios_exported_headers = {

packages/react-native-codegen/src/generators/components/GenerateComponentHObjCpp.js

@@ -43,8 +43,8 @@ const protocolTemplate = `
 `.trim();
 
 const commandHandlerIfCaseConvertArgTemplate = `
-#if RCT_DEBUG
   NSObject *arg::_ARG_NUMBER_:: = args[::_ARG_NUMBER_::];
+#if RCT_DEBUG
   if (!RCTValidateTypeOfViewCommandArgument(arg::_ARG_NUMBER_::, ::_EXPECTED_KIND_::, @"::_EXPECTED_KIND_STRING_::", @"::_COMPONENT_NAME_::", commandName, @"::_ARG_NUMBER_STR_::")) {
     return;
   }

packages/react-native-codegen/src/generators/components/__tests__/__snapshots__/GenerateComponentHObjCpp-test.js.snap

@@ -139,40 +139,40 @@ if ([commandName isEqualToString:@\\"allTypes\\"]) {
   }
 #endif
 
-  #if RCT_DEBUG
   NSObject *arg0 = args[0];
+#if RCT_DEBUG
   if (!RCTValidateTypeOfViewCommandArgument(arg0, [NSNumber class], @\\"number\\", @\\"CommandNativeComponent\\", commandName, @\\"1st\\")) {
     return;
   }
 #endif
   NSInteger x = [(NSNumber *)arg0 intValue];
 
+NSObject *arg1 = args[1];
 #if RCT_DEBUG
-  NSObject *arg1 = args[1];
   if (!RCTValidateTypeOfViewCommandArgument(arg1, [NSNumber class], @\\"float\\", @\\"CommandNativeComponent\\", commandName, @\\"2nd\\")) {
     return;
   }
 #endif
   float y = [(NSNumber *)arg1 floatValue];
 
+NSObject *arg2 = args[2];
 #if RCT_DEBUG
-  NSObject *arg2 = args[2];
   if (!RCTValidateTypeOfViewCommandArgument(arg2, [NSNumber class], @\\"double\\", @\\"CommandNativeComponent\\", commandName, @\\"3rd\\")) {
     return;
   }
 #endif
   double z = [(NSNumber *)arg2 doubleValue];
 
+NSObject *arg3 = args[3];
 #if RCT_DEBUG
-  NSObject *arg3 = args[3];
   if (!RCTValidateTypeOfViewCommandArgument(arg3, [NSString class], @\\"string\\", @\\"CommandNativeComponent\\", commandName, @\\"4th\\")) {
     return;
   }
 #endif
   NSString * message = (NSString *)arg3;
 
+NSObject *arg4 = args[4];
 #if RCT_DEBUG
-  NSObject *arg4 = args[4];
   if (!RCTValidateTypeOfViewCommandArgument(arg4, [NSNumber class], @\\"boolean\\", @\\"CommandNativeComponent\\", commandName, @\\"5th\\")) {
     return;
   }
@@ -224,16 +224,16 @@ RCT_EXTERN inline void RCTCommandNativeComponentHandleCommand(
   }
 #endif
 
-  #if RCT_DEBUG
   NSObject *arg0 = args[0];
+#if RCT_DEBUG
   if (!RCTValidateTypeOfViewCommandArgument(arg0, [NSNumber class], @\\"number\\", @\\"CommandNativeComponent\\", commandName, @\\"1st\\")) {
     return;
   }
 #endif
   NSInteger x = [(NSNumber *)arg0 intValue];
 
+NSObject *arg1 = args[1];
 #if RCT_DEBUG
-  NSObject *arg1 = args[1];
   if (!RCTValidateTypeOfViewCommandArgument(arg1, [NSNumber class], @\\"number\\", @\\"CommandNativeComponent\\", commandName, @\\"2nd\\")) {
     return;
   }