Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/bindings/v8/ScriptPromiseResolverWithContext.h

Index: Source/bindings/v8/ScriptPromiseResolverWithContext.h
diff --git a/Source/bindings/v8/ScriptPromiseResolverWithContext.h b/Source/bindings/v8/ScriptPromiseResolverWithContext.h
index 0ccf94e1c1d77195839cb79d9341d22c808fd0b2..798e3e28686aca4b67576900bcb64b3168a58978 100644
--- a/Source/bindings/v8/ScriptPromiseResolverWithContext.h
+++ b/Source/bindings/v8/ScriptPromiseResolverWithContext.h
@@ -31,13 +31,24 @@ class ScriptPromiseResolverWithContext : public ActiveDOMObject, public RefCount
     WTF_MAKE_NONCOPYABLE(ScriptPromiseResolverWithContext);
 
 public:
-    static PassRefPtr<ScriptPromiseResolverWithContext> create(ScriptState* scriptState)
+    enum Mode {
+        Default,
+        KeepAliveWhilePending,
+    };
+
+    // Create a ScriptPromiseResolverWithContext.
+    // If |mode| is KeepAliveWhilePending, the resolver refers itself in order
+    // to stay alive while the promise is pending and the associated
+    // ExecutionContext isn't stopped.
+    static PassRefPtr<ScriptPromiseResolverWithContext> create(ScriptState* scriptState, Mode mode = Default)
     {
-        RefPtr<ScriptPromiseResolverWithContext> resolver = adoptRef(new ScriptPromiseResolverWithContext(scriptState));
+        RefPtr<ScriptPromiseResolverWithContext> resolver = adoptRef(new ScriptPromiseResolverWithContext(scriptState, mode));
         resolver->suspendIfNeeded();
         return resolver.release();
     }
 
+    virtual ~ScriptPromiseResolverWithContext();
+
     // Anything that can be passed to toV8Value can be passed to this function.
     template <typename T>
     void resolve(T value)
@@ -69,7 +80,7 @@ public:
     virtual void stop() OVERRIDE;
 
 protected:
-    explicit ScriptPromiseResolverWithContext(ScriptState*);
+    ScriptPromiseResolverWithContext(ScriptState*, Mode);
 
 private:
     enum ResolutionState {
@@ -90,6 +101,7 @@ private:
     {
         if (m_state != Pending || !executionContext() || executionContext()->activeDOMObjectsAreStopped())
             return;
+        ASSERT(newState == Resolving || newState == Rejecting);
         m_state = newState;
         // Retain this object until it is actually resolved or rejected.
         // |deref| will be called in |clear|.
@@ -107,6 +119,7 @@ private:
 
     ResolutionState m_state;
     const RefPtr<ScriptState> m_scriptState;
+    Mode m_mode;
     Timer<ScriptPromiseResolverWithContext> m_timer;
     RefPtr<ScriptPromiseResolver> m_resolver;
     ScopedPersistent<v8::Value> m_value;