Expand the visible parts of the android bridge a little bit

Reviewed By: javache

Differential Revision: D4560212

fbshipit-source-id: 7591ff825fd51ae5b3d3f494c677c75d75388471

ReactAndroid/src/main/java/com/facebook/react/cxxbridge/JavaModuleWrapper.java

@@ -40,7 +40,7 @@ import static com.facebook.systrace.Systrace.TRACE_TAG_REACT_JAVA_BRIDGE;
  */
 
 @DoNotStrip
-/* package */ class JavaModuleWrapper {
+public class JavaModuleWrapper {
   @DoNotStrip
   public class MethodDescriptor {
     @DoNotStrip

ReactAndroid/src/main/jni/xreact/jni/BUCK

@@ -2,7 +2,10 @@ include_defs("//ReactAndroid/DEFS")
 
 EXPORTED_HEADERS = [
     "CxxModuleWrapper.h",
+    "JavaModuleWrapper.h",
+    "JExecutorToken.h",
     "JSLoader.h",
+    "MethodInvoker.h",
     "NativeArray.h",
     "NativeCommon.h",
     "NativeMap.h",
@@ -20,7 +23,6 @@ cxx_library(
         "-Werror",
         "-fexceptions",
         "-std=c++1y",
-        "-fvisibility=hidden",
         "-frtti",
         "-Wno-pessimizing-move",
         "-Wno-inconsistent-missing-override",