Implement the Windows desktop search redirection feature.

components/search_engines/desktop_search_utils_win.h

+// Copyright 2016 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 COMPONENTS_SEARCH_ENGINES_DESKTOP_SEARCH_UTILS_WIN_H_
+#define COMPONENTS_SEARCH_ENGINES_DESKTOP_SEARCH_UTILS_WIN_H_
+
+#include "base/feature_list.h"
+#include "base/strings/string16.h"
+#include "url/gurl.h"
+
+class PrefService;
+class TemplateURLService;
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+namespace prefs {
+// Name of the preference keeping track of whether the Windows desktop search
+// redirection infobar has already been shown.
+extern const char kWindowsDesktopSearchRedirectionInfobarShownPref[];
+}  // namespace prefs
+
+// Windows desktop search redirection feature. This is exposed in the header
+// file so that it can be referenced from about_flags.cc.
+extern const base::Feature kWindowsDesktopSearchRedirectionFeature;
+
+// Registers the Windows desktop search redirection preference into |registry|.
+void RegisterWindowsDesktopSearchRedirectionPref(
+    user_prefs::PrefRegistrySyncable* registry);
+
+// Replaces |url| by a default search engine URL if it is a desktop search URL
+// and these conditions are met:
+// - The Windows desktop search redirection feature is enabled.
+// - The default search engine is not Bing.
+// |should_show_infobar| is set to true if an infobar should be shown to tell
+// the user that a redirection occurred.
+void ReplaceWindowsDesktopSearchURLWithDefaultSearchURLIfNeeded(
+    const PrefService* pref_service,
+    TemplateURLService* template_url_service,
+    GURL* url,
+    bool* should_show_infobar);

[Peter Kasting, 2016/01/20 03:03:02]

Why doesn't this return a bool instead of taking it as an outparam?  Seems like
that would be simpler, and would simplify the test code slightly too.

[fdoray, 2016/01/21 21:02:34]

Done.

+
+#endif  // COMPONENTS_SEARCH_ENGINES_DESKTOP_SEARCH_UTILS_WIN_H_