Revert of Remove ContextLifecycleObserver from ScriptPromisePropertyBase

third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h

Index: third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h b/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h
index 379dcc2de8fcff6c079a3436e6b9f7595f8c24df..ef03a45b31bb914664a089bd21855a80f46bbf62 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyBase.h
@@ -9,6 +9,7 @@
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseProperties.h"
 #include "core/CoreExport.h"
+#include "core/dom/ContextLifecycleObserver.h"
 #include "wtf/Compiler.h"
 #include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
@@ -23,7 +24,10 @@
 
 // TODO(yhirano): Remove NEVER_INLINE once we find the cause of crashes.
 class CORE_EXPORT ScriptPromisePropertyBase
-    : public GarbageCollectedFinalized<ScriptPromisePropertyBase> {
+    : public GarbageCollectedFinalized<ScriptPromisePropertyBase>,
+      public ContextLifecycleObserver {
+  USING_GARBAGE_COLLECTED_MIXIN(ScriptPromisePropertyBase);
+
  public:
   virtual ~ScriptPromisePropertyBase();
 
@@ -39,7 +43,7 @@
     Rejected,
   };
   State getState() const { return m_state; }
-  ExecutionContext* getExecutionContext() const;
+
   ScriptPromise promise(DOMWrapperWorld&);
 
   DECLARE_VIRTUAL_TRACE();
@@ -81,7 +85,6 @@
   v8::Local<v8::String> promiseName();
   v8::Local<v8::String> resolverName();
 
-  Member<ExecutionContext> m_executionContext;
   v8::Isolate* m_isolate;
   Name m_name;
   State m_state;