[Media Router] Clean up issues related code.

chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h

Index: chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h
diff --git a/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h b/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h
index 4a9156d42c7a6c7be3f690c589fbf13f53edfc5b..8d8e15204f0661a2cecd3dde78bf976c79987efd 100644
--- a/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h
+++ b/chrome/browser/ui/webui/media_router/media_router_webui_message_handler.h
@@ -48,9 +48,8 @@ class MediaRouterWebUIMessageHandler : public content::WebUIMessageHandler {
                                      const MediaRoute* route);
   void ReturnSearchResult(const std::string& sink_id);
 
-  // Does not take ownership of |issue|. Note that |issue| can be nullptr, when
-  // there are no more issues.
-  void UpdateIssue(const Issue* issue);
+  void UpdateIssue(const Issue& issue);
+  void ClearIssue();
 
   // Updates the maximum dialog height to allow the WebUI properly scale when
   // the browser window changes.
@@ -90,7 +89,7 @@ class MediaRouterWebUIMessageHandler : public content::WebUIMessageHandler {
   // Performs an action for an Issue of |type|.
   // |args| contains additional parameter that varies based on |type|.
   // Returns |true| if the action was successfully performed.
-  bool ActOnIssueType(const IssueAction::Type& type,
+  bool ActOnIssueType(IssueInfo::Action type,
                       const base::DictionaryValue* args);
 
   // May update the first run flow related properties in the WebUI. This is