Add missing (and remove superfluous) 'explicit' from constructors.

chrome/browser/autofill/autocomplete_history_manager_unittest.cc

 // Copyright (c) 2012 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 <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/autofill/autocomplete_history_manager.h"
@@ skipping 154 matching lines @@
                     const std::vector<string16>& autofill_labels,
                     const std::vector<string16>& autofill_icons,
                     const std::vector<int>& autofill_unique_ids));
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockAutofillExternalDelegate);
 };
 
 class AutocompleteHistoryManagerStubSend : public AutocompleteHistoryManager {
  public:
-  explicit AutocompleteHistoryManagerStubSend(
+  AutocompleteHistoryManagerStubSend(
       WebContents* web_contents,
       Profile* profile,
       scoped_ptr<AutofillWebDataService> wds)
       : AutocompleteHistoryManager(web_contents, profile, wds.Pass()) {}
 
   // Intentionally swallow the message.
   virtual bool Send(IPC::Message* message) { delete message; return true; }
 };
 
 }  // namespace
 
 // Make sure our external delegate is called at the right time.
 TEST_F(AutocompleteHistoryManagerTest, ExternalDelegate) {
   // Local version with a stubbed out Send()
   AutocompleteHistoryManagerStubSend autocomplete_history_manager(
       web_contents(),
       &profile_,
       scoped_ptr<AutofillWebDataService>(
           new AutofillWebDataServiceImpl(web_data_service_)));
 
   MockAutofillExternalDelegate external_delegate(web_contents());
   EXPECT_CALL(external_delegate, OnSuggestionsReturned(_, _,  _,  _,  _));
   autocomplete_history_manager.SetExternalDelegate(&external_delegate);
 
   // Should trigger a call to OnSuggestionsReturned, verified by the mock.
   autocomplete_history_manager.SendSuggestions(NULL);
 }