8 files changed, 23 insertions, 9 deletions
diff --git a/fxjs/cjs_document.cpp b/fxjs/cjs_document.cpp
index 248116b69a..9cfcad313e 100644
--- a/fxjs/cjs_document.cpp
+++ b/fxjs/cjs_document.cpp
@@ -132,8 +132,7 @@ CJS_Document::CJS_Document(v8::Local<v8::Object> pObject)
 CJS_Document::~CJS_Document() = default;
 
 void CJS_Document::InitInstance(IJS_Runtime* pIRuntime) {
-  CJS_Runtime* pRuntime = static_cast<CJS_Runtime*>(pIRuntime);
-  SetFormFillEnv(pRuntime->GetFormFillEnv());
+  SetFormFillEnv(pIRuntime->GetFormFillEnv());
 }
 
 // The total number of fields in document.
diff --git a/fxjs/cjs_global.cpp b/fxjs/cjs_global.cpp
index c8deadf5d5..282b26210f 100644
--- a/fxjs/cjs_global.cpp
+++ b/fxjs/cjs_global.cpp
@@ -214,8 +214,7 @@ CJS_Global::~CJS_Global() {
 }
 
 void CJS_Global::InitInstance(IJS_Runtime* pIRuntime) {
-  CJS_Runtime* pRuntime = static_cast<CJS_Runtime*>(pIRuntime);
-  Initial(pRuntime->GetFormFillEnv());
+  Initial(pIRuntime->GetFormFillEnv());
 }
 
 void CJS_Global::Initial(CPDFSDK_FormFillEnvironment* pFormFillEnv) {
diff --git a/fxjs/cjs_runtime.cpp b/fxjs/cjs_runtime.cpp
index b9b9c03e1b..3a607f1aae 100644
--- a/fxjs/cjs_runtime.cpp
+++ b/fxjs/cjs_runtime.cpp
@@ -143,6 +143,10 @@ void CJS_Runtime::DefineJSObjects() {
   CJS_Annot::DefineJSObjects(this);
 }
 
+CJS_Runtime* CJS_Runtime::AsCJSRuntime() {
+  return this;
+}
+
 IJS_EventContext* CJS_Runtime::NewEventContext() {
   m_EventContextArray.push_back(pdfium::MakeUnique<CJS_EventContext>(this));
   return m_EventContextArray.back().get();
diff --git a/fxjs/cjs_runtime.h b/fxjs/cjs_runtime.h
index 0aab84828f..c5e69fbdc8 100644
--- a/fxjs/cjs_runtime.h
+++ b/fxjs/cjs_runtime.h
@@ -33,6 +33,7 @@ class CJS_Runtime : public IJS_Runtime,
   ~CJS_Runtime() override;
 
   // IJS_Runtime
+  CJS_Runtime* AsCJSRuntime() override;
   IJS_EventContext* NewEventContext() override;
   void ReleaseEventContext(IJS_EventContext* pContext) override;
   CPDFSDK_FormFillEnvironment* GetFormFillEnv() const override;
diff --git a/fxjs/cjs_runtimestub.cpp b/fxjs/cjs_runtimestub.cpp
index 98c7679a04..c1e680e5d5 100644
--- a/fxjs/cjs_runtimestub.cpp
+++ b/fxjs/cjs_runtimestub.cpp
@@ -14,6 +14,10 @@ CJS_RuntimeStub::CJS_RuntimeStub(CPDFSDK_FormFillEnvironment* pFormFillEnv)
 
 CJS_RuntimeStub::~CJS_RuntimeStub() = default;
 
+CJS_Runtime* CJS_RuntimeStub::AsCJSRuntime() {
+  return nullptr;
+}
+
 IJS_EventContext* CJS_RuntimeStub::NewEventContext() {
   if (!m_pContext)
     m_pContext = pdfium::MakeUnique<CJS_EventContextStub>();
diff --git a/fxjs/cjs_runtimestub.h b/fxjs/cjs_runtimestub.h
index ecf3b4eb8a..a9e85fdf03 100644
--- a/fxjs/cjs_runtimestub.h
+++ b/fxjs/cjs_runtimestub.h
@@ -21,6 +21,7 @@ class CJS_RuntimeStub final : public IJS_Runtime {
   explicit CJS_RuntimeStub(CPDFSDK_FormFillEnvironment* pFormFillEnv);
   ~CJS_RuntimeStub() override;
 
+  CJS_Runtime* AsCJSRuntime() override;
   IJS_EventContext* NewEventContext() override;
   void ReleaseEventContext(IJS_EventContext* pContext) override;
   CPDFSDK_FormFillEnvironment* GetFormFillEnv() const override;
diff --git a/fxjs/ijs_runtime.cpp b/fxjs/ijs_runtime.cpp
index 03538cd7b5..79238bfe11 100644
--- a/fxjs/ijs_runtime.cpp
+++ b/fxjs/ijs_runtime.cpp
@@ -31,8 +31,10 @@ void IJS_Runtime::Destroy() {
 std::unique_ptr<IJS_Runtime> IJS_Runtime::Create(
     CPDFSDK_FormFillEnvironment* pFormFillEnv) {
 #ifdef PDF_ENABLE_V8
-  return pdfium::MakeUnique<CJS_Runtime>(pFormFillEnv);
-#else
-  return pdfium::MakeUnique<CJS_RuntimeStub>(pFormFillEnv);
+  if (pFormFillEnv->IsJSPlatformPresent())
+    return pdfium::MakeUnique<CJS_Runtime>(pFormFillEnv);
 #endif
+  return pdfium::MakeUnique<CJS_RuntimeStub>(pFormFillEnv);
 }
+
+IJS_Runtime::~IJS_Runtime() = default;
diff --git a/fxjs/ijs_runtime.h b/fxjs/ijs_runtime.h
index b97c65ef90..cde31c6e52 100644
--- a/fxjs/ijs_runtime.h
+++ b/fxjs/ijs_runtime.h
@@ -16,18 +16,22 @@
 #include "fxjs/fxjse.h"
 #endif  // PDF_ENABLE_XFA
 
+class CJS_Runtime;
 class CPDFSDK_FormFillEnvironment;
 class IJS_EventContext;
 
-// Owns the FJXS objects needed to actually execute JS.
+// Owns the FJXS objects needed to actually execute JS, if possible. This
+// virtual interface is backed by either an actual JS runtime, or a stub,
+// when JS is not present.
 class IJS_Runtime {
  public:
   static void Initialize(unsigned int slot, void* isolate);
   static void Destroy();
   static std::unique_ptr<IJS_Runtime> Create(
       CPDFSDK_FormFillEnvironment* pFormFillEnv);
-  virtual ~IJS_Runtime() {}
+  virtual ~IJS_Runtime();
 
+  virtual CJS_Runtime* AsCJSRuntime() = 0;
   virtual IJS_EventContext* NewEventContext() = 0;
   virtual void ReleaseEventContext(IJS_EventContext* pContext) = 0;
   virtual CPDFSDK_FormFillEnvironment* GetFormFillEnv() const = 0;