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

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

Index: chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc
diff --git a/chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc b/chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc
index ea235fab38ea5438c83fe98b847a90568b04d54d..ef318b5c6d75de2d146fba0f7640475f22ef72dd 100644
--- a/chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc
+++ b/chrome/browser/ui/webui/settings/settings_clear_browsing_data_handler.cc
@@ -41,14 +41,13 @@ 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() {
@@ -73,9 +72,12 @@ void ClearBrowsingDataHandler::OnJavascriptAllowed() {
 
   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();
 }
@@ -83,7 +85,7 @@ void ClearBrowsingDataHandler::OnJavascriptDisallowed() {
 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_));
@@ -163,17 +165,18 @@ void ClearBrowsingDataHandler::HandleClearBrowsingData(
 
   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::OnBrowsingDataRemoverDone() {
-  remover_->RemoveObserver(this);
-  remover_ = nullptr;
+void ClearBrowsingDataHandler::OnBrowsingDataRemoving(bool is_removing) {
+  CallJavascriptFunction("cr.webUIListenerCallback",
+                         base::StringValue("browsing-data-removing"),
+                         base::FundamentalValue(is_removing));
+}
 
+void ClearBrowsingDataHandler::OnBrowsingDataRemoverDone() {
   PrefService* prefs = profile_->GetPrefs();
   int notice_shown_times =
       prefs->GetInteger(prefs::kClearBrowsingDataHistoryNoticeShownTimes);
@@ -214,6 +217,8 @@ void ClearBrowsingDataHandler::OnBrowsingHistoryPrefChanged() {
 
 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_)));
@@ -226,6 +231,9 @@ void ClearBrowsingDataHandler::HandleInitialize(const base::ListValue* args) {
 
   OnStateChanged();
   RefreshHistoryNotice();
+  OnBrowsingDataRemoving(remover_->is_removing());
+
+  ResolveJavascriptCallback(*callback_id, *base::Value::CreateNullValue());
 }
 
 void ClearBrowsingDataHandler::OnStateChanged() {