Oilpan: add missing tracing of WebLocalFrameImpls from inspector agents.

third_party/WebKit/Source/web/InspectorEmulationAgent.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef InspectorEmulationAgent_h
 #define InspectorEmulationAgent_h
 
 #include "core/InspectorFrontend.h"
 #include "core/inspector/InspectorBaseAgent.h"
 
@@ skipping 24 matching lines @@
     void restore() override;
     void discardAgent() override;
     void didCommitLoadForLocalFrame(LocalFrame*) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit InspectorEmulationAgent(WebLocalFrameImpl*);
     WebViewImpl* webViewImpl();
 
-    WebLocalFrameImpl* m_webLocalFrameImpl;
+    RawPtrWillBeMember<WebLocalFrameImpl> m_webLocalFrameImpl;
 };
 
 
 } // namespace blink
 
 
 #endif // !defined(InspectorEmulationAgent_h)