Make NewNull return an actual Null

This CL updates the CFXJS_Engine::NewNull method to return a real v8::Null
instead of an empty v8::Local. This also adds a NewUndefined and returns
undefined in most of the places null was returned previously.

Change-Id: If1a96bf253057892a3b709cbc72f8825c52503c3
Reviewed-on: https://pdfium-review.googlesource.com/16730
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

3 files changed, 21 insertions, 2 deletions

diff --git a/fxjs/fxjs_v8.cpp b/fxjs/fxjs_v8.cpp
index 4c6398870d..441848205f 100644
--- a/fxjs/fxjs_v8.cpp
+++ b/fxjs/fxjs_v8.cpp
@@ -664,7 +664,11 @@ v8::Local<v8::String> CFXJS_Engine::NewString(const WideStringView& str) {
 }
 
 v8::Local<v8::Value> CFXJS_Engine::NewNull() {
-  return v8::Local<v8::Value>();
+  return v8::Null(m_isolate);
+}
+
+v8::Local<v8::Value> CFXJS_Engine::NewUndefined() {
+  return v8::Undefined(m_isolate);
 }
 
 v8::Local<v8::Date> CFXJS_Engine::NewDate(double d) {
diff --git a/fxjs/fxjs_v8.h b/fxjs/fxjs_v8.h
index f5e52411f3..eee85e031d 100644
--- a/fxjs/fxjs_v8.h
+++ b/fxjs/fxjs_v8.h
@@ -179,6 +179,7 @@ class CFXJS_Engine {
   v8::Local<v8::Object> GetThisObj();
 
   v8::Local<v8::Value> NewNull();
+  v8::Local<v8::Value> NewUndefined();
   v8::Local<v8::Array> NewArray();
   v8::Local<v8::Number> NewNumber(int number);
   v8::Local<v8::Number> NewNumber(double number);
diff --git a/fxjs/fxjs_v8_embeddertest.cpp b/fxjs/fxjs_v8_embeddertest.cpp
index 53fe8f268b..d975264d1d 100644
--- a/fxjs/fxjs_v8_embeddertest.cpp
+++ b/fxjs/fxjs_v8_embeddertest.cpp
@@ -98,11 +98,25 @@ TEST_F(FXJSV8EmbedderTest, NewNull) {
   EXPECT_FALSE(engine()->ToBoolean(nullz));
   EXPECT_EQ(0, engine()->ToInt32(nullz));
   EXPECT_EQ(0.0, engine()->ToDouble(nullz));
-  EXPECT_EQ(L"", engine()->ToWideString(nullz));
+  EXPECT_EQ(L"null", engine()->ToWideString(nullz));
   EXPECT_TRUE(engine()->ToObject(nullz).IsEmpty());
   EXPECT_TRUE(engine()->ToArray(nullz).IsEmpty());
 }
 
+TEST_F(FXJSV8EmbedderTest, NewUndefined) {
+  v8::Isolate::Scope isolate_scope(isolate());
+  v8::HandleScope handle_scope(isolate());
+  v8::Context::Scope context_scope(GetV8Context());
+
+  auto undef = engine()->NewUndefined();
+  EXPECT_FALSE(engine()->ToBoolean(undef));
+  EXPECT_EQ(0, engine()->ToInt32(undef));
+  EXPECT_TRUE(std::isnan(engine()->ToDouble(undef)));
+  EXPECT_EQ(L"undefined", engine()->ToWideString(undef));
+  EXPECT_TRUE(engine()->ToObject(undef).IsEmpty());
+  EXPECT_TRUE(engine()->ToArray(undef).IsEmpty());
+}
+
 TEST_F(FXJSV8EmbedderTest, NewBoolean) {
   v8::Isolate::Scope isolate_scope(isolate());
   v8::HandleScope handle_scope(isolate());