[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 144 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(prefs::kDeleteTimePeriod);
   remover_ = BrowsingDataRemoverFactory::GetForBrowserContext(profile_);
   remover_->AddObserver(this);

[Dan Beam, 2016/07/06 22:13:06]

so we already are observing things globally (i.e. if you make 2 settings pages,
they both get notified in OnBrowsingDataRemoverDone() because they're requesting
the same profile-keyed BrowsingDataRemover*)

i vote we just change the observer from OnBrowsingDataRemoverDone() to
OnBrowserDataRemoverChanged(bool removing)

[dschuyler, 2016/07/07 01:25:33]

I called it OnBrowserDataRemoving(bool is_removing)

   remover_->Remove(
       BrowsingDataRemover::Period(
           static_cast<BrowsingDataRemover::TimePeriod>(period_selected)),
       remove_mask, origin_mask);
 }
 
 void ClearBrowsingDataHandler::OnBrowsingDataRemoverDone() {
   remover_->RemoveObserver(this);
   remover_ = nullptr;
 
@@ skipping 30 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()));
   AddCounter(base::WrapUnique(new CacheCounter()));
   AddCounter(base::WrapUnique(new DownloadsCounter()));
   AddCounter(base::WrapUnique(new HistoryCounter()));
   AddCounter(base::WrapUnique(new HostedAppsCounter()));
   AddCounter(base::WrapUnique(new PasswordsCounter()));
   AddCounter(base::WrapUnique(new MediaLicensesCounter()));
 
   OnStateChanged();
   RefreshHistoryNotice();
+
+  ResolveJavascriptCallback(*callback_id, base::FundamentalValue(!!remover_));
 }
 
 void ClearBrowsingDataHandler::OnStateChanged() {
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("update-footer"),
       base::FundamentalValue(sync_service_ && sync_service_->IsSyncActive()),
       base::FundamentalValue(show_history_footer_));
 }
 
@@ skipping 47 matching lines @@
 void ClearBrowsingDataHandler::UpdateCounterText(
     std::unique_ptr<BrowsingDataCounter::Result> result) {
   CallJavascriptFunction(
       "cr.webUIListenerCallback",
       base::StringValue("update-counter-text"),
       base::StringValue(result->source()->GetPrefName()),
       base::StringValue(GetCounterTextFromResult(result.get())));
 }
 
 }  // namespace settings