Allow OSExchangeData::Provider to be overridden at run time.

ui/base/dragdrop/os_exchange_data.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 "ui/base/dragdrop/os_exchange_data.h"
 
 #include "base/pickle.h"
 #include "build/build_config.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_factory.h"
 #include "url/gurl.h"
 
 namespace ui {
 
 OSExchangeData::DownloadFileInfo::DownloadFileInfo(
     const base::FilePath& filename,
     DownloadFileProvider* downloader)
     : filename(filename),
       downloader(downloader) {
 }
 
 OSExchangeData::DownloadFileInfo::~DownloadFileInfo() {}
 
-OSExchangeData::OSExchangeData() : provider_(CreateProvider()) {
+OSExchangeData::OSExchangeData()
+    : provider_(OSExchangeDataProviderFactory::CreateProvider()) {
 }
 
-OSExchangeData::OSExchangeData(Provider* provider) : provider_(provider) {
+OSExchangeData::OSExchangeData(std::unique_ptr<Provider> provider)
+    : provider_(std::move(provider)) {
 }
 
 OSExchangeData::~OSExchangeData() {
 }
 
 void OSExchangeData::MarkOriginatedFromRenderer() {
   provider_->MarkOriginatedFromRenderer();
 }
 
 bool OSExchangeData::DidOriginateFromRenderer() const {
@@ skipping 106 matching lines @@
 void OSExchangeData::SetHtml(const base::string16& html, const GURL& base_url) {
   provider_->SetHtml(html, base_url);
 }
 
 bool OSExchangeData::GetHtml(base::string16* html, GURL* base_url) const {
   return provider_->GetHtml(html, base_url);
 }
 #endif
 
 }  // namespace ui