Refactor fxjs_v8 and add embeddertests for it.

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 e0c8938c34b02dbf8021b1fe63271fee479300c1..41d75717ae57961522e5b72d938c1c41a5abb086 100644
--- a/fpdfsdk/src/jsapi/fxjs_v8.cpp
+++ b/fpdfsdk/src/jsapi/fxjs_v8.cpp
@@ -75,6 +75,28 @@ class CJS_ObjDefintion {
   v8::Global<v8::Object> m_StaticObj;
 };
 
+void* JS_ArrayBufferAllocator::Allocate(size_t length) {
+  return calloc(1, length);
+}
+
+void* JS_ArrayBufferAllocator::AllocateUninitialized(size_t length) {
+  return malloc(length);
+}
+
+void JS_ArrayBufferAllocator::Free(void* data, size_t length) {
+  free(data);
+}
+
+void JS_PrepareIsolate(v8::Isolate* pIsolate) {
+  if (!pIsolate->GetData(g_embedderDataSlot))
+    pIsolate->SetData(g_embedderDataSlot, new CFX_PtrArray());
+}
+
+void JS_ResetIsolate(v8::Isolate* pIsolate) {
+  delete (CFX_PtrArray*)pIsolate->GetData(g_embedderDataSlot);
+  pIsolate->SetData(g_embedderDataSlot, nullptr);
+}
+
 int JS_DefineObj(v8::Isolate* pIsolate,
                  const wchar_t* sObjName,
                  FXJSOBJTYPE eObjType,
@@ -82,11 +104,9 @@ int JS_DefineObj(v8::Isolate* pIsolate,
                  LP_DESTRUCTOR pDestructor) {
   v8::Isolate::Scope isolate_scope(pIsolate);
   v8::HandleScope handle_scope(pIsolate);
+
+  JS_PrepareIsolate(pIsolate);
   CFX_PtrArray* pArray = (CFX_PtrArray*)pIsolate->GetData(g_embedderDataSlot);
-  if (!pArray) {
-    pArray = new CFX_PtrArray();
-    pIsolate->SetData(g_embedderDataSlot, pArray);
-  }
   CJS_ObjDefintion* pObjDef = new CJS_ObjDefintion(pIsolate, sObjName, eObjType,
                                                    pConstructor, pDestructor);
   pArray->Add(pObjDef);