Add unit test for WebRTCInternalsMessageHandler.

content/browser/media/webrtc/webrtc_internals_message_handler.h

 // Copyright (c) 2013 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 CONTENT_BROWSER_MEDIA_WEBRTC_WEBRTC_INTERNALS_MESSAGE_HANDLER_H_
 #define CONTENT_BROWSER_MEDIA_WEBRTC_WEBRTC_INTERNALS_MESSAGE_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/browser/media/webrtc/webrtc_internals_ui_observer.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 namespace base {
 class ListValue;
 }  // namespace base
 
 namespace content {
 
 class RenderFrameHost;
+class WebRTCInternals;
 
 // This class handles messages to and from WebRTCInternalsUI.
 // It delegates all its work to WebRTCInternalsProxy on the IO thread.
-class WebRTCInternalsMessageHandler : public WebUIMessageHandler,
-                                      public WebRTCInternalsUIObserver{
+class CONTENT_EXPORT WebRTCInternalsMessageHandler
+    : public WebUIMessageHandler,
+      public NON_EXPORTED_BASE(WebRTCInternalsUIObserver) {
  public:
   WebRTCInternalsMessageHandler();
   ~WebRTCInternalsMessageHandler() override;
 
   // WebUIMessageHandler implementation.
   void RegisterMessages() override;
 
   // WebRTCInternalsUIObserver override.
   void OnUpdate(const std::string& command, const base::Value* args) override;
 
+ protected:
+  // The WebRTCInternals to use. Always WebRTCInternals::GetInstance()
+  // except for testing.
+  explicit WebRTCInternalsMessageHandler(WebRTCInternals* webrtc_internals);
+  WebRTCInternals* const webrtc_internals_;
+
  private:
   // Returns a pointer to the RFH iff it is currently hosting the
   // webrtc-internals page.
   RenderFrameHost* GetWebRTCInternalsHost() const;
 
   // Javascript message handler.
   void OnGetAllStats(const base::ListValue* list);
   void OnSetAudioDebugRecordingsEnabled(bool enable,
                                         const base::ListValue* list);
   void OnSetEventLogRecordingsEnabled(bool enable, const base::ListValue* list);
   void OnDOMLoadDone(const base::ListValue* list);
 
   DISALLOW_COPY_AND_ASSIGN(WebRTCInternalsMessageHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_WEBRTC_WEBRTC_INTERNALS_MESSAGE_HANDLER_H_