downloads: add the ability to undo download removal.

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 <set>
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 171 matching lines @@
                download_danger_type_enum_changed);
 
 // Note: Any change to the state strings, should be accompanied by a
 // corresponding change to downloads.json.
 const char* const kStateStrings[] = {
   kStateInProgress,
   kStateComplete,
   kStateInterrupted,
   kStateInterrupted,
 };
-COMPILE_ASSERT(arraysize(kStateStrings) == DownloadItem::MAX_DOWNLOAD_STATE,
+COMPILE_ASSERT(arraysize(kStateStrings) == DownloadItem::MAX_DOWNLOAD_STATE - 1,

[Dan Beam, 2014/11/13 02:51:16]

i couldn't find this file and wasn't sure what to do here.  please advise.

                download_item_state_enum_changed);
 
 const char* DangerString(content::DownloadDangerType danger) {
   DCHECK(danger >= 0);
   DCHECK(danger < static_cast<content::DownloadDangerType>(
       arraysize(kDangerStrings)));
   if (danger < 0 || danger >= static_cast<content::DownloadDangerType>(
       arraysize(kDangerStrings)))
     return "";
   return kDangerStrings[danger];
@@ skipping 1729 matching lines @@
     const Extension* extension,
     UnloadedExtensionInfo::Reason reason) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   std::set<const Extension*>::iterator iter =
       shelf_disabling_extensions_.find(extension);
   if (iter != shelf_disabling_extensions_.end())
     shelf_disabling_extensions_.erase(iter);
 }
 
 }  // namespace extensions