Prepare ClearBrowsingDataDialogFragment for browsing data counters.

chrome/browser/browsing_data/browsing_data_counter_utils.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/browsing_data/browsing_data_counter_utils.h"
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/browsing_data/autofill_counter.h"
 #include "chrome/browser/browsing_data/cache_counter.h"
@@ skipping 150 matching lines @@
                                           displayed_strings[2]);
         break;
       default:
         NOTREACHED();
     }
   }
 
   return text;
 }
 
+bool GetDeletionPreferenceFromDataType(
+    BrowsingDataType data_type, std::string* out_pref) {
+  switch (data_type) {
+    case HISTORY:
+      *out_pref = prefs::kDeleteBrowsingHistory;
+      return true;
+    case CACHE:
+      *out_pref = prefs::kDeleteCache;
+      return true;
+    case COOKIES:
+      *out_pref = prefs::kDeleteCookies;
+      return true;
+    case PASSWORDS:
+      *out_pref = prefs::kDeletePasswords;
+      return true;
+    case FORM_DATA:
+      *out_pref = prefs::kDeleteFormData;
+      return true;
+    case BOOKMARKS:
+      // Bookmarks are deleted on the Android side. No corresponding deletion
+      // preference.
+      return false;
+    default:

[Bernhard Bauer, 2016/01/14 16:12:43]

Replace this with NUM_TYPES please, so that the compiler will check that you've
covered all the cases ☺

[msramek, 2016/01/14 18:03:33]

Done. Unfortunately, since |data_type| can possibly be out of range, this
requires additional return after the switch.

[Bernhard Bauer, 2016/01/14 18:23:00]

Yes, but that's what NOTREACHED() is for. :)

(I think you could probably fall out of the switch statement and only use one
NOTREACHED()).

[msramek, 2016/01/14 18:37:58]

It came to my mind, but I decided for a separate NOTREACHED() in the NUM_TYPES
case, so that the case is self-contained and doesn't rely on code outside the
switch.

+      NOTREACHED();
+      return false;
+  }
+}
+
 BrowsingDataCounter* CreateCounterForPreference(std::string pref_name) {
   if (!AreCountersEnabled())
     return nullptr;
 
   if (pref_name == prefs::kDeleteBrowsingHistory)
     return new HistoryCounter();
   if (pref_name == prefs::kDeleteCache)
     return new CacheCounter();
   if (pref_name == prefs::kDeletePasswords)
     return new PasswordsCounter();
   if (pref_name == prefs::kDeleteFormData)
     return new AutofillCounter();
 
   return nullptr;
 }