[Downloads] Always call DM::StartDownload() for explicit downloads.

chrome/browser/extensions/api/downloads/downloads_api.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 "chrome/browser/extensions/api/downloads/downloads_api.h"
 
 #include <algorithm>
 #include <cctype>
 #include <iterator>
 #include <set>
@@ skipping 1027 matching lines @@
 }
 
 void DownloadsDownloadFunction::OnStarted(
     const base::FilePath& creator_suggested_filename,
     downloads::FilenameConflictAction creator_conflict_action,
     DownloadItem* item,
     content::DownloadInterruptReason interrupt_reason) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   VLOG(1) << __FUNCTION__ << " " << item << " " << interrupt_reason;
   if (item) {
-    DCHECK_EQ(content::DOWNLOAD_INTERRUPT_REASON_NONE, interrupt_reason);
     SetResult(new base::FundamentalValue(static_cast<int>(item->GetId())));
     if (!creator_suggested_filename.empty()) {
       ExtensionDownloadsEventRouterData* data =
           ExtensionDownloadsEventRouterData::Get(item);
       if (!data) {
         data = new ExtensionDownloadsEventRouterData(
             item,
             scoped_ptr<base::DictionaryValue>(new base::DictionaryValue()));
       }
       data->CreatorSuggestedFilename(
           creator_suggested_filename, creator_conflict_action);
     }
     new DownloadedByExtension(
         item, GetExtension()->id(), GetExtension()->name());
     item->UpdateObservers();
   } else {
-    DCHECK_NE(content::DOWNLOAD_INTERRUPT_REASON_NONE, interrupt_reason);
     error_ = content::DownloadInterruptReasonToString(interrupt_reason);
   }
   SendResponse(error_.empty());
 }
 
 DownloadsSearchFunction::DownloadsSearchFunction() {}
 
 DownloadsSearchFunction::~DownloadsSearchFunction() {}
 
 bool DownloadsSearchFunction::RunImpl() {
@@ skipping 822 matching lines @@
       extensions::UnloadedExtensionInfo* unloaded =
           content::Details<extensions::UnloadedExtensionInfo>(details).ptr();
       std::set<const extensions::Extension*>::iterator iter =
         shelf_disabling_extensions_.find(unloaded->extension);
       if (iter != shelf_disabling_extensions_.end())
         shelf_disabling_extensions_.erase(iter);
       break;
     }
   }
 }