[Bindings] Replace V8HiddenValue in generated code with V8PrivateProperty

third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp

Index: third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp b/third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp
index 141a8426f20404c2afa61835d9fdbd345b6510c0..cc62b5f4f247fee86321eedc47911cc72b8eda46 100644
--- a/third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/custom/V8PopStateEventCustom.cpp
@@ -32,21 +32,25 @@
 
 #include "bindings/core/v8/SerializedScriptValue.h"
 #include "bindings/core/v8/SerializedScriptValueFactory.h"
-#include "bindings/core/v8/V8HiddenValue.h"
 #include "bindings/core/v8/V8History.h"
+#include "bindings/core/v8/V8PrivateProperty.h"
 #include "core/events/PopStateEvent.h"
 #include "core/frame/History.h"
 
 namespace blink {
 
+namespace {
+// kSymbolKey must be equal to the key in generated V8History.cpp
+constexpr char kSymbolKey[] = "History#State";

[Yuki, 2017/03/31 13:38:29]

Could you add a TODO comment, here?
This is abuse or invalid use of [CachedAttribute].

[peria, 2017/04/03 04:58:43]

Done.

+}
+
 // Save the state value to a hidden attribute in the V8PopStateEvent, and return
 // it, for convenience.
 static v8::Local<v8::Value> cacheState(ScriptState* scriptState,
                                        v8::Local<v8::Object> popStateEvent,
                                        v8::Local<v8::Value> state) {
-  V8HiddenValue::setHiddenValue(scriptState, popStateEvent,
-                                V8HiddenValue::state(scriptState->isolate()),
-                                state);
+  V8PrivateProperty::createSymbol(scriptState->isolate(), kSymbolKey)

[Yuki, 2017/03/31 13:38:29]

We don't need to kSymbolKey for |popStateEvent| or |info.Holder()|.

[peria, 2017/04/03 04:58:43]

Done.

+      .set(popStateEvent, state);
   return state;
 }
 
@@ -54,10 +58,11 @@ void V8PopStateEvent::stateAttributeGetterCustom(
     const v8::FunctionCallbackInfo<v8::Value>& info) {
   v8::Isolate* isolate = info.GetIsolate();
   ScriptState* scriptState = ScriptState::current(isolate);
-  v8::Local<v8::Value> result = V8HiddenValue::getHiddenValue(
-      scriptState, info.Holder(), V8HiddenValue::state(isolate));
+  V8PrivateProperty::Symbol propertySymbol =
+      V8PrivateProperty::createSymbol(isolate, kSymbolKey);
+  v8::Local<v8::Value> result = propertySymbol.getOrUndefined(info.Holder());
 
-  if (!result.IsEmpty()) {
+  if (!result->IsUndefined()) {

[Yuki, 2017/03/31 13:38:29]

Are you sure that the state attribute never be undefined?

[peria, 2017/04/03 04:58:43]

State must be a serializable object, and "undefined" is serializable.
Fixed the code.

     v8SetReturnValue(info, result);
     return;
   }
@@ -93,17 +98,14 @@ void V8PopStateEvent::stateAttributeGetterCustom(
     if (v8HistoryValue.IsEmpty())
       return;
     v8::Local<v8::Object> v8History = v8HistoryValue.As<v8::Object>();
-    if (!history->stateChanged()) {
-      result = V8HiddenValue::getHiddenValue(scriptState, v8History,
-                                             V8HiddenValue::state(isolate));
-      if (!result.IsEmpty()) {
-        v8SetReturnValue(info, cacheState(scriptState, info.Holder(), result));
-        return;
-      }
+    if (!history->stateChanged() && propertySymbol.hasValue(v8History)) {

[Yuki, 2017/03/31 13:38:29]

I don't think that this part is performance sensitive, and the spec doesn't
require that the attribute must return the same object as History.state.  So, in
a follow-up CL, we could stop using this.
https://html.spec.whatwg.org/multipage/browsers.html#the-popstateevent-interface

[peria, 2017/04/03 04:58:43]

Acknowledged.

+      v8SetReturnValue(info,
+                       cacheState(scriptState, info.Holder(),
+                                  propertySymbol.getOrUndefined(v8History)));
+      return;
     }
     result = event->serializedState()->deserialize(isolate);
-    V8HiddenValue::setHiddenValue(scriptState, v8History,
-                                  V8HiddenValue::state(isolate), result);
+    propertySymbol.set(v8History, result);
   } else {
     result = event->serializedState()->deserialize(isolate);
   }