diff --git a/fxjs/xfa/cfxjse_context.cpp b/fxjs/xfa/cfxjse_context.cpp
index 953448d..0606037 100644
--- a/fxjs/xfa/cfxjse_context.cpp
+++ b/fxjs/xfa/cfxjse_context.cpp
@@ -15,6 +15,7 @@
 #include "fxjs/xfa/cfxjse_runtimedata.h"
 #include "fxjs/xfa/cfxjse_value.h"
 #include "fxjs/xfa/cjx_object.h"
+#include "third_party/base/ptr_util.h"
 #include "xfa/fxfa/parser/cxfa_thisproxy.h"
 
 namespace {
@@ -130,15 +131,6 @@
   hObject->SetAlignedPointerInInternalField(1, nullptr);
 }
 
-CXFA_ThisProxy* ToThisProxy(CFXJSE_Value* pValue) {
-  CFXJSE_HostObject* pHostObject = pValue->ToHostObject();
-  if (!pHostObject)
-    return nullptr;
-
-  CJX_Object* pJSObject = pHostObject->AsCJXObject();
-  return pJSObject ? ToThisProxy(pJSObject->GetXFAObject()) : nullptr;
-}
-
 }  // namespace
 
 void FXJSE_UpdateObjectBinding(v8::Local<v8::Object> hObject,
@@ -184,9 +176,13 @@
 std::unique_ptr<CFXJSE_Context> CFXJSE_Context::Create(
     v8::Isolate* pIsolate,
     const FXJSE_CLASS_DESCRIPTOR* pGlobalClass,
-    CFXJSE_HostObject* pGlobalObject) {
+    CFXJSE_HostObject* pGlobalObject,
+    std::unique_ptr<CXFA_ThisProxy> pProxy) {
   CFXJSE_ScopeUtil_IsolateHandle scope(pIsolate);
-  auto pContext = std::make_unique<CFXJSE_Context>(pIsolate);
+
+  // Private constructor.
+  auto pContext =
+      pdfium::WrapUnique(new CFXJSE_Context(pIsolate, std::move(pProxy)));
   v8::Local<v8::ObjectTemplate> hObjectTemplate;
   if (pGlobalClass) {
     CFXJSE_Class* pGlobalClassObj =
@@ -218,14 +214,11 @@
   return pContext;
 }
 
-CFXJSE_Context::CFXJSE_Context(v8::Isolate* pIsolate) : m_pIsolate(pIsolate) {}
+CFXJSE_Context::CFXJSE_Context(v8::Isolate* pIsolate,
+                               std::unique_ptr<CXFA_ThisProxy> pProxy)
+    : m_pIsolate(pIsolate), m_pProxy(std::move(pProxy)) {}
 
-CFXJSE_Context::~CFXJSE_Context() {
-  // This is what prevents leaking the CXFA_ThisProxies allocated in
-  // CXFJSE_Engine::CreateVariablesContext(). If the global object is
-  // not a thisproxy, then this degenerates to deleting nullptr, a no-op.
-  delete ToThisProxy(GetGlobalObject().get());
-}
+CFXJSE_Context::~CFXJSE_Context() = default;
 
 std::unique_ptr<CFXJSE_Value> CFXJSE_Context::GetGlobalObject() {
   auto pValue = std::make_unique<CFXJSE_Value>(GetIsolate());
diff --git a/fxjs/xfa/cfxjse_context.h b/fxjs/xfa/cfxjse_context.h
index 417cf23..ed302f0 100644
--- a/fxjs/xfa/cfxjse_context.h
+++ b/fxjs/xfa/cfxjse_context.h
@@ -17,6 +17,7 @@
 class CFXJSE_Class;
 class CFXJSE_HostObject;
 class CFXJSE_Value;
+class CXFA_ThisProxy;
 struct FXJSE_CLASS_DESCRIPTOR;
 
 class CFXJSE_Context {
@@ -24,9 +25,9 @@
   static std::unique_ptr<CFXJSE_Context> Create(
       v8::Isolate* pIsolate,
       const FXJSE_CLASS_DESCRIPTOR* pGlobalClass,
-      CFXJSE_HostObject* pGlobalObject);
+      CFXJSE_HostObject* pGlobalObject,
+      std::unique_ptr<CXFA_ThisProxy> pProxy);
 
-  explicit CFXJSE_Context(v8::Isolate* pIsolate);
   ~CFXJSE_Context();
 
   v8::Isolate* GetIsolate() const { return m_pIsolate.Get(); }
@@ -40,12 +41,14 @@
                      CFXJSE_Value* lpNewThisObject);
 
  private:
+  CFXJSE_Context(v8::Isolate* pIsolate, std::unique_ptr<CXFA_ThisProxy> pProxy);
   CFXJSE_Context(const CFXJSE_Context&) = delete;
   CFXJSE_Context& operator=(const CFXJSE_Context&) = delete;
 
   v8::Global<v8::Context> m_hContext;
   UnownedPtr<v8::Isolate> m_pIsolate;
   std::vector<std::unique_ptr<CFXJSE_Class>> m_rgClasses;
+  std::unique_ptr<CXFA_ThisProxy> m_pProxy;
 };
 
 void FXJSE_UpdateObjectBinding(v8::Local<v8::Object> hObject,
diff --git a/fxjs/xfa/cfxjse_engine.cpp b/fxjs/xfa/cfxjse_engine.cpp
index fbfd008..44836c9 100644
--- a/fxjs/xfa/cfxjse_engine.cpp
+++ b/fxjs/xfa/cfxjse_engine.cpp
@@ -108,7 +108,8 @@
       m_pDocument(pDocument),
       m_JsContext(CFXJSE_Context::Create(fxjs_runtime->GetIsolate(),
                                          &GlobalClassDescriptor,
-                                         pDocument->GetRoot()->JSObject())),
+                                         pDocument->GetRoot()->JSObject(),
+                                         nullptr)),
       m_ResolveProcessor(std::make_unique<CFXJSE_ResolveProcessor>()) {
   RemoveBuiltInObjs(m_JsContext.get());
   m_JsContext->EnableCompatibleMode();
@@ -499,12 +500,10 @@
   if (!pScriptNode || !pSubform)
     return nullptr;
 
-  // Ownership of |proxy| is maintained through v8 bindings, and is
-  // manually freed in ~CFXJE_Context() after re-obtaining the binding
-  // from v8.
-  auto* proxy = new CXFA_ThisProxy(pSubform, pScriptNode);
+  auto proxy = std::make_unique<CXFA_ThisProxy>(pSubform, pScriptNode);
+  CJX_Object* js_object = proxy->JSObject();
   auto pNewContext = CFXJSE_Context::Create(
-      GetIsolate(), &VariablesClassDescriptor, proxy->JSObject());
+      GetIsolate(), &VariablesClassDescriptor, js_object, std::move(proxy));
   RemoveBuiltInObjs(pNewContext.get());
   pNewContext->EnableCompatibleMode();
   CFXJSE_Context* pResult = pNewContext.get();
diff --git a/fxjs/xfa/cfxjse_formcalc_context.cpp b/fxjs/xfa/cfxjse_formcalc_context.cpp
index d93f3b7..f25c263 100644
--- a/fxjs/xfa/cfxjse_formcalc_context.cpp
+++ b/fxjs/xfa/cfxjse_formcalc_context.cpp
@@ -28,6 +28,7 @@
 #include "xfa/fxfa/parser/cxfa_document.h"
 #include "xfa/fxfa/parser/cxfa_localevalue.h"
 #include "xfa/fxfa/parser/cxfa_node.h"
+#include "xfa/fxfa/parser/cxfa_thisproxy.h"
 #include "xfa/fxfa/parser/cxfa_timezoneprovider.h"
 #include "xfa/fxfa/parser/xfa_utils.h"
 
@@ -3208,7 +3209,7 @@
   }
 
   std::unique_ptr<CFXJSE_Context> pNewContext(
-      CFXJSE_Context::Create(pIsolate, nullptr, nullptr));
+      CFXJSE_Context::Create(pIsolate, nullptr, nullptr, nullptr));
 
   auto returnValue = std::make_unique<CFXJSE_Value>(pIsolate);
   pNewContext->ExecuteScript(