[MD settings] disable clear browsing data while it is running

chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.h"
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 23 matching lines @@
 const int kMaxTimesHistoryNoticeShown = 1;
 
 }
 
 namespace settings {
 
 ClearBrowsingDataHandler::ClearBrowsingDataHandler(content::WebUI* webui)
     : profile_(Profile::FromWebUI(webui)),
       sync_service_(ProfileSyncServiceFactory::GetForProfile(profile_)),
       sync_service_observer_(this),
-      remover_(nullptr),
+      remover_(BrowsingDataRemoverFactory::GetForBrowserContext(profile_)),

[Dan Beam, 2016/07/07 18:06:49]

is there any big penalty for creating this from construction?  i.e. why was this
lazily accessed before?

[dschuyler, 2016/07/20 19:01:15]

Good point. Even if the penalty is not big, it's non-zero work that doesn't need
to be
done at startup. I moved it back to being lazy (though not the exact spot it was
before).

Done.

       show_history_footer_(false),
       show_history_deletion_dialog_(false),
       weak_ptr_factory_(this) {}
 
 ClearBrowsingDataHandler::~ClearBrowsingDataHandler() {
-  if (remover_)
-    remover_->RemoveObserver(this);
+  remover_->RemoveObserver(this);

[Dan Beam, 2016/07/07 18:06:49]

can you make this a ScopedObserver like sync_service_observer_?

[dschuyler, 2016/07/20 19:01:14]

Done.

 }
 
 void ClearBrowsingDataHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback(
       "clearBrowsingData",
       base::Bind(&ClearBrowsingDataHandler::HandleClearBrowsingData,
                  base::Unretained(this)));
 
   web_ui()->RegisterMessageCallback(
       "initializeClearBrowsingData",
       base::Bind(&ClearBrowsingDataHandler::HandleInitialize,
                  base::Unretained(this)));
 }
 
 void ClearBrowsingDataHandler::OnJavascriptAllowed() {
   PrefService* prefs = profile_->GetPrefs();
   profile_pref_registrar_.Init(prefs);
   profile_pref_registrar_.Add(
       prefs::kAllowDeletingBrowserHistory,
       base::Bind(&ClearBrowsingDataHandler::OnBrowsingHistoryPrefChanged,
                  base::Unretained(this)));
 
   if (sync_service_)
     sync_service_observer_.Add(sync_service_);
+
+  remover_->AddObserver(this);
 }
 
 void ClearBrowsingDataHandler::OnJavascriptDisallowed() {
+  remover_->RemoveObserver(this);
   profile_pref_registrar_.RemoveAll();
   sync_service_observer_.RemoveAll();
 }
 
 void ClearBrowsingDataHandler::HandleClearBrowsingData(
     const base::ListValue* args) {
   // We should never be called when the previous clearing has not yet finished.
-  CHECK(!remover_);
+  CHECK(!remover_->is_removing());
   CHECK_EQ(1U, args->GetSize());
   CHECK(webui_callback_id_.empty());
   CHECK(args->GetString(0, &webui_callback_id_));
 
   PrefService* prefs = profile_->GetPrefs();
 
   int site_data_mask = BrowsingDataRemover::REMOVE_SITE_DATA;
   // Don't try to clear LSO data if it's not supported.
   if (!prefs->GetBoolean(prefs::kClearPluginLSODataEnabled))
     site_data_mask &= ~BrowsingDataRemover::REMOVE_PLUGIN_DATA;
@@ skipping 59 matching lines @@
     int checked_other_types = std::count_if(
         other_types, other_types + num_other_types,
         [prefs](const std::string& pref) { return prefs->GetBoolean(pref); });
     UMA_HISTOGRAM_SPARSE_SLOWLY(
         "History.ClearBrowsingData.PasswordsDeletion.AdditionalDatatypesCount",
         checked_other_types);
   }
 
   int period_selected =
       prefs->GetInteger(browsing_data::prefs::kDeleteTimePeriod);
-  remover_ = BrowsingDataRemoverFactory::GetForBrowserContext(profile_);
-  remover_->AddObserver(this);
   remover_->Remove(BrowsingDataRemover::Period(
                        static_cast<browsing_data::TimePeriod>(period_selected)),
                    remove_mask, origin_mask);
 }
 
+void ClearBrowsingDataHandler::OnBrowsingDataRemoving(bool is_removing) {
+  CallJavascriptFunction("cr.webUIListenerCallback",
+                         base::StringValue("browsing-data-removing"),
+                         base::FundamentalValue(is_removing));
+}
+
 void ClearBrowsingDataHandler::OnBrowsingDataRemoverDone() {
-  remover_->RemoveObserver(this);
-  remover_ = nullptr;
-
   PrefService* prefs = profile_->GetPrefs();
   int notice_shown_times =
       prefs->GetInteger(prefs::kClearBrowsingDataHistoryNoticeShownTimes);
 
   // When the deletion is complete, we might show an additional dialog with
   // a notice about other forms of browsing history. This is the case if
   const bool show_notice =
       // 1. The dialog is relevant for the user.
       show_history_deletion_dialog_ &&
       // 2. The notice has been shown less than |kMaxTimesHistoryNoticeShown|.
@@ skipping 20 matching lines @@
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("browsing-history-pref-changed"),
       base::FundamentalValue(
           profile_->GetPrefs()->GetBoolean(
               prefs::kAllowDeletingBrowserHistory)));
 }
 
 void ClearBrowsingDataHandler::HandleInitialize(const base::ListValue* args) {
   AllowJavascript();
+  const base::Value* callback_id;
+  CHECK(args->Get(0, &callback_id));
 
   // TODO(msramek): Simplify this using a factory.
   AddCounter(base::WrapUnique(new AutofillCounter(profile_)));
   AddCounter(base::WrapUnique(new CacheCounter(profile_)));
   AddCounter(base::WrapUnique(new DownloadsCounter(profile_)));
   AddCounter(base::WrapUnique(new HistoryCounter(profile_)));
   AddCounter(base::WrapUnique(new HostedAppsCounter(profile_)));
   AddCounter(base::WrapUnique(new PasswordsCounter(profile_)));
   AddCounter(base::WrapUnique(new MediaLicensesCounter(profile_)));
 
   OnStateChanged();
   RefreshHistoryNotice();
+  OnBrowsingDataRemoving(remover_->is_removing());
+
+  ResolveJavascriptCallback(*callback_id, *base::Value::CreateNullValue());
 }
 
 void ClearBrowsingDataHandler::OnStateChanged() {
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("update-footer"),
       base::FundamentalValue(sync_service_ && sync_service_->IsSyncActive()),
       base::FundamentalValue(show_history_footer_));
 }
 
@@ skipping 46 matching lines @@
 void ClearBrowsingDataHandler::UpdateCounterText(
     std::unique_ptr<browsing_data::BrowsingDataCounter::Result> result) {
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("update-counter-text"),
       base::StringValue(result->source()->GetPrefName()),
       base::StringValue(GetCounterTextFromResult(result.get())));
 }
 
 }  // namespace settings