Only call DefineJSObjects() once for the global V8 isolate.

fpdfsdk/src/jsapi/fxjs_v8.cpp

Index: fpdfsdk/src/jsapi/fxjs_v8.cpp
diff --git a/fpdfsdk/src/jsapi/fxjs_v8.cpp b/fpdfsdk/src/jsapi/fxjs_v8.cpp
index bea9f4c4d88a2ce15fabbb1f6d2917eeeac43745..54044e2118a38797c659be94ed0f7d2bd77d7ff9 100644
--- a/fpdfsdk/src/jsapi/fxjs_v8.cpp
+++ b/fpdfsdk/src/jsapi/fxjs_v8.cpp
@@ -166,6 +166,10 @@ bool FXJS_GetIsolate(v8::Isolate** pResultIsolate) {
   return true;
 }
 
+size_t FXJS_GlobalIsolateRefCount() {
+  return g_isolate_ref_count;
+}
+
 // static
 void FXJS_PerIsolateData::SetUp(v8::Isolate* pIsolate) {
   if (!pIsolate->GetData(g_embedderDataSlot))