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

chrome/browser/ui/webui/fileicon_source_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 "base/memory/ref_counted_memory.h"
 #include "base/message_loop.h"
 #include "chrome/browser/icon_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/fileicon_source.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 using content::BrowserThread;
 
 namespace {
 
 class TestFileIconSource : public FileIconSource {
  public:
-  explicit TestFileIconSource() {}
+  TestFileIconSource() {}
 
   MOCK_METHOD4(FetchFileIcon, void(const FilePath& path,
                                    ui::ScaleFactor scale_factor,
                                    IconLoader::IconSize icon_size,
                                    int request_id));
 
  private:
   virtual ~TestFileIconSource() {}
 };
 
@@ skipping 83 matching lines @@
 TEST_F(FileIconSourceTest, FileIconSource_Parse) {
   for (unsigned i = 0; i < arraysize(kBasicExpectations); i++) {
     scoped_refptr<TestFileIconSource> source(CreateFileIconSource());
     EXPECT_CALL(*source.get(),
                 FetchFileIcon(FilePath(kBasicExpectations[i].unescaped_path),
                               kBasicExpectations[i].scale_factor,
                               kBasicExpectations[i].size, i));
     source->StartDataRequest(kBasicExpectations[i].request_path, false, i);
   }
 }