Rename ContextDestructionObserver to ContextLifecycleObserver

Source/bindings/v8/V8MutationCallback.h

Index: Source/bindings/v8/V8MutationCallback.h
diff --git a/Source/bindings/v8/V8MutationCallback.h b/Source/bindings/v8/V8MutationCallback.h
index b60f2f14ff90d4639dbf59a0e7fe444b0b04a31d..27fe4b855dc94395c4b41911680363cee844a7e7 100644
--- a/Source/bindings/v8/V8MutationCallback.h
+++ b/Source/bindings/v8/V8MutationCallback.h
@@ -47,7 +47,7 @@ public:
     }
 
     virtual void call(const Vector<RefPtr<MutationRecord> >&, MutationObserver*) OVERRIDE;
-    virtual ScriptExecutionContext* scriptExecutionContext() const OVERRIDE { return ContextDestructionObserver::scriptExecutionContext(); }
+    virtual ScriptExecutionContext* scriptExecutionContext() const OVERRIDE { return ContextLifecycleObserver::scriptExecutionContext(); }
 
 private:
     V8MutationCallback(v8::Handle<v8::Function>, ScriptExecutionContext*, v8::Handle<v8::Object>, v8::Isolate*);