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

chrome/browser/extensions/api/downloads/downloads_api_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 <algorithm>
 
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/json/json_reader.h"
 #include "base/message_loop.h"
@@ skipping 599 matching lines @@
     }
   }
 
  private:
   DownloadManager::DownloadVector* items_;
   DISALLOW_COPY_AND_ASSIGN(ScopedItemVectorCanceller);
 };
 
 class TestProtocolHandler : public net::URLRequestJobFactory::ProtocolHandler {
  public:
-  explicit TestProtocolHandler(
+  TestProtocolHandler(
       webkit_blob::BlobStorageController* blob_storage_controller,
       fileapi::FileSystemContext* file_system_context)
       : blob_storage_controller_(blob_storage_controller),
         file_system_context_(file_system_context) {}
 
   virtual ~TestProtocolHandler() {}
 
   virtual net::URLRequestJob* MaybeCreateJob(
       net::URLRequest* request,
       net::NetworkDelegate* network_delegate) const OVERRIDE {
@@ skipping 1518 matching lines @@
                           "  \"state\": {"
                           "    \"previous\": \"in_progress\","
                           "    \"current\": \"complete\"}}]",
                           result_id,
                           GetFilename("on_record.txt.crdownload").c_str(),
                           GetFilename("on_record.txt").c_str())));
   std::string disk_data;
   EXPECT_TRUE(file_util::ReadFileToString(item->GetFullPath(), &disk_data));
   EXPECT_STREQ(kPayloadData, disk_data.c_str());
 }