Remove LifecycleNotifier<>::m_context.

Source/platform/LifecycleContextTest.cpp

Index: Source/platform/LifecycleContextTest.cpp
diff --git a/Source/platform/LifecycleContextTest.cpp b/Source/platform/LifecycleContextTest.cpp
index 7998adfe22cd8bffef9967c90c532ebd363cc255..bf33b9028e3f2a2ffcdf528d5ac39eba6c558fb6 100644
--- a/Source/platform/LifecycleContextTest.cpp
+++ b/Source/platform/LifecycleContextTest.cpp
@@ -27,7 +27,9 @@
 #include "config.h"
 
 #include "platform/LifecycleNotifier.h"
+#include "platform/LifecycleObserver.h"
 #include "platform/heap/Handle.h"
+
 #include <gtest/gtest.h>
 
 using namespace blink;
@@ -43,26 +45,10 @@ public:
         return adoptPtrWillBeNoop(new DummyContext());
     }
 
-    void addObserver(TestingObserver* observer)
-    {
-        LifecycleNotifier<DummyContext, TestingObserver>::addObserver(observer);
-    }
-
-    void removeObserver(TestingObserver* observer)
-    {
-        LifecycleNotifier<DummyContext, TestingObserver>::removeObserver(observer);
-    }
-
     DEFINE_INLINE_TRACE()
     {
         LifecycleNotifier<DummyContext, TestingObserver>::trace(visitor);
     }
-
-private:
-    DummyContext()
-        : LifecycleNotifier<DummyContext, TestingObserver>(this)
-    {
-    }
 };
 
 class TestingObserver final : public NoBaseWillBeGarbageCollectedFinalized<TestingObserver>, public LifecycleObserver<DummyContext, TestingObserver, DummyContext> {