Implement important sites dialog for desktop.

chrome/browser/browsing_data/browsing_data_important_sites_util.h

+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_IMPORTANT_SITES_UTIL_H_
+#define CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_IMPORTANT_SITES_UTIL_H_
+
+#include "chrome/browser/browsing_data/chrome_browsing_data_remover_delegate.h"
+#include "components/browsing_data/core/browsing_data_utils.h"
+#include "content/public/browser/browsing_data_remover.h"
+
+namespace content {
+class BrowsingDataFilterBuilder;
+}
+
+namespace browsing_data_important_sites_util {
+
+// Deletes the types protected by Important Sites with the filter from
+// |filter_builder|, the other types are deleted completely.
+// The observer will be called twice.
+void Remove(int remove_mask,

[msramek, 2017/05/05 09:12:59]

When I call a method and pass it an |observer|, my expectation is that it will
call |observer| once when finished.

This method will always call it twice. Note that we are using a special class in
browsing_data_bridge which converts the two callbacks into one.

At the very least, please document the behavior; but ideally, move that class
into browsing_data_important_sites_util.cc and merge the two callbacks. The
caller has no need to know that we require two calls to BrowsingDataRemover to
execute this deletion.

[dullweber, 2017/05/05 11:51:54]

I moved the Observer class to the util file and pass a OnceCallback instead.
Previously the task_observer was destroyed in HandleInitialize and
JavascriptDisabled. I replaced these resets with a weak_ptr invalidation. This
will also kill all other requests using the weak_ptr_factory but I guess that it
was the intention to not receive responses from old requests after these events
anyway?

+            int origin_mask,
+            browsing_data::TimePeriod time_period,
+            std::unique_ptr<content::BrowsingDataFilterBuilder> filter_builder,
+            content::BrowsingDataRemover* remover,
+            content::BrowsingDataRemover::Observer* observer);
+
+}  // namespace browsing_data_important_sites_util
+
+#endif  // CHROME_BROWSER_BROWSING_DATA_BROWSING_DATA_IMPORTANT_SITES_UTIL_H_