Convert SupervisedUserResourceThrottle to a NavigationThrottle.

chrome/browser/ui/webui/supervised_user_internals_message_handler.cc

Index: chrome/browser/ui/webui/supervised_user_internals_message_handler.cc
diff --git a/chrome/browser/ui/webui/supervised_user_internals_message_handler.cc b/chrome/browser/ui/webui/supervised_user_internals_message_handler.cc
index 6018d646028377c5c21829b4bac8400bdd1df039..63e4126215e0c89ed3db4fa3f0ffaf5c91afe5ad 100644
--- a/chrome/browser/ui/webui/supervised_user_internals_message_handler.cc
+++ b/chrome/browser/ui/webui/supervised_user_internals_message_handler.cc
@@ -20,6 +20,7 @@
 #include "chrome/browser/supervised_user/supervised_user_service_factory.h"
 #include "chrome/browser/supervised_user/supervised_user_settings_service.h"
 #include "chrome/browser/supervised_user/supervised_user_settings_service_factory.h"
+#include "chrome/browser/supervised_user/supervised_user_url_filter.h"
 #include "chrome/common/channel_info.h"
 #include "components/signin/core/browser/account_tracker_service.h"
 #include "components/supervised_user_error_page/supervised_user_error_page.h"
@@ -114,61 +115,8 @@ std::string FilteringBehaviorReasonToString(
 
 }  // namespace
 
-// Helper class that lives on the IO thread, listens to the
-// SupervisedUserURLFilter there, and posts results back to the UI thread.
-class SupervisedUserInternalsMessageHandler::IOThreadHelper
-    : public base::RefCountedThreadSafe<IOThreadHelper,
-                                        BrowserThread::DeleteOnIOThread>,
-      public SupervisedUserURLFilter::Observer {
- public:
-  using OnURLCheckedCallback =
-      base::Callback<void(const GURL&,
-                          SupervisedUserURLFilter::FilteringBehavior,
-                          supervised_user_error_page::FilteringBehaviorReason,
-                          bool uncertain)>;
-
-  IOThreadHelper(scoped_refptr<const SupervisedUserURLFilter> filter,
-                 const OnURLCheckedCallback& callback)
-      : filter_(filter), callback_(callback) {
-    BrowserThread::PostTask(BrowserThread::IO,
-                            FROM_HERE,
-                            base::Bind(&IOThreadHelper::InitOnIOThread, this));
-  }
-
- private:
-  friend class base::DeleteHelper<IOThreadHelper>;
-  friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
-  virtual ~IOThreadHelper() {
-    DCHECK_CURRENTLY_ON(BrowserThread::IO);
-    filter_->RemoveObserver(this);
-  }
-
-  // SupervisedUserURLFilter::Observer:
-  void OnSiteListUpdated() override {}
-  void OnURLChecked(const GURL& url,
-                    SupervisedUserURLFilter::FilteringBehavior behavior,
-                    supervised_user_error_page::FilteringBehaviorReason reason,
-                    bool uncertain) override {
-    BrowserThread::PostTask(BrowserThread::UI,
-                            FROM_HERE,
-                            base::Bind(callback_,
-                                       url, behavior, reason, uncertain));
-  }
-
-  void InitOnIOThread() {
-    DCHECK_CURRENTLY_ON(BrowserThread::IO);
-    filter_->AddObserver(this);
-  }
-
-  scoped_refptr<const SupervisedUserURLFilter> filter_;
-  OnURLCheckedCallback callback_;
-
-  DISALLOW_COPY_AND_ASSIGN(IOThreadHelper);
-};
-
 SupervisedUserInternalsMessageHandler::SupervisedUserInternalsMessageHandler()
-    : weak_factory_(this) {
-}
+    : scoped_observer_(this), weak_factory_(this) {}
 
 SupervisedUserInternalsMessageHandler::
     ~SupervisedUserInternalsMessageHandler() {
@@ -205,13 +153,10 @@ SupervisedUserInternalsMessageHandler::GetSupervisedUserService() {
 void SupervisedUserInternalsMessageHandler::HandleRegisterForEvents(
     const base::ListValue* args) {
   DCHECK(args->empty());
+  if (scoped_observer_.IsObservingSources())
+    return;
 
-  if (!io_thread_helper_.get()) {
-    io_thread_helper_ = new IOThreadHelper(
-        GetSupervisedUserService()->GetURLFilterForIOThread(),
-        base::Bind(&SupervisedUserInternalsMessageHandler::OnURLChecked,
-                   weak_factory_.GetWeakPtr()));
-  }
+  scoped_observer_.Add(GetSupervisedUserService()->GetURLFilter());
 }
 
 void SupervisedUserInternalsMessageHandler::HandleGetBasicInfo(
@@ -230,8 +175,7 @@ void SupervisedUserInternalsMessageHandler::HandleTryURL(
   if (!url.is_valid())
     return;
 
-  SupervisedUserURLFilter* filter =
-      GetSupervisedUserService()->GetURLFilterForUIThread();
+  SupervisedUserURLFilter* filter = GetSupervisedUserService()->GetURLFilter();
   std::map<std::string, base::string16> whitelists =
       filter->GetMatchingWhitelistTitles(url);
   filter->GetFilteringBehaviorForURLWithAsyncChecks(
@@ -256,8 +200,7 @@ void SupervisedUserInternalsMessageHandler::SendBasicInfo() {
                   profile->IsLegacySupervised());
   AddSectionEntry(section_profile, "Child", profile->IsChild());
 
-  SupervisedUserURLFilter* filter =
-      GetSupervisedUserService()->GetURLFilterForUIThread();
+  SupervisedUserURLFilter* filter = GetSupervisedUserService()->GetURLFilter();
 
   base::ListValue* section_filter = AddSection(section_list.get(), "Filter");
   AddSectionEntry(section_filter, "Blacklist active", filter->HasBlacklist());
@@ -327,6 +270,8 @@ void SupervisedUserInternalsMessageHandler::OnTryURLResult(
       "chrome.supervised_user_internals.receiveTryURLResult", result);
 }
 
+void SupervisedUserInternalsMessageHandler::OnSiteListUpdated() {}
+
 void SupervisedUserInternalsMessageHandler::OnURLChecked(
     const GURL& url,
     SupervisedUserURLFilter::FilteringBehavior behavior,