Implemented 'Reset Search engines' feature.

chrome/browser/search_engines/template_url_prepopulate_data.cc

Index: chrome/browser/search_engines/template_url_prepopulate_data.cc
diff --git a/chrome/browser/search_engines/template_url_prepopulate_data.cc b/chrome/browser/search_engines/template_url_prepopulate_data.cc
index 235f621966a62123151a531121ec714b2b6dfccf..efbb266f60d75054491325c8be38a0273f8bed8f 100644
--- a/chrome/browser/search_engines/template_url_prepopulate_data.cc
+++ b/chrome/browser/search_engines/template_url_prepopulate_data.cc
@@ -1197,6 +1197,16 @@ void GetPrepopulatedTemplateFromPrefs(Profile* profile,
   }
 }
 
+void ClearPrepopulatedEnginesInPrefs(Profile* profile) {
+  if (!profile)
+    return;
+
+  PrefService* prefs = profile->GetPrefs();
+  DCHECK(prefs);
+  prefs->ClearPref(prefs::kSearchProviderOverrides);
+  prefs->ClearPref(prefs::kSearchProviderOverridesVersion);
+}
+
 // The caller owns the returned TemplateURL.
 TemplateURL* MakePrepopulatedTemplateURLFromPrepopulateEngine(
     Profile* profile,