Try one more time to lock down content sniffing for

chrome/browser/download/download_manager.cc

 // Copyright (c) 2006-2009 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/download/download_manager.h"
 
 #include "app/l10n_util.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 91 matching lines @@
 
 static bool DownloadPathIsDangerous(const FilePath& download_path) {
   FilePath desktop_dir;
   if (!PathService::Get(chrome::DIR_USER_DESKTOP, &desktop_dir)) {
     NOTREACHED();
     return false;
   }
   return (download_path == desktop_dir);
 }
 
-// Helper to determine if a download is a Chrome extension. We should be able to
-// just use the mime type, but even our own servers are not setup to serve the
-// right headers yet, so we have a short-term file extension heuristic, too.
-static bool IsChromeExtension(const FilePath& path,
-                              const std::string& mime_type) {
-  // If the server says it is an extension, it is definitely an extension.
-  if (mime_type == Extension::kMimeType)
-    return true;
-
-  // Otherwise, it is an extension if it has the right, err, extension.
-  return path.Extension().size() > 1 &&
-         path.Extension().substr(1) == chrome::kExtensionFileExtension;
-}
-
 // DownloadItem implementation -------------------------------------------------
 
 // Constructor for reading from the history service.
 DownloadItem::DownloadItem(const DownloadCreateInfo& info)
     : id_(-1),
       full_path_(info.path),
       url_(info.url),
       referrer_url_(info.referrer_url),
       mime_type_(info.mime_type),
       total_bytes_(info.total_bytes),
@@ skipping 442 matching lines @@
   else
     info->suggested_path = download_path();
   info->suggested_path = info->suggested_path.Append(generated_name);
 
   if (!info->save_as) {
     // Downloads can be marked as dangerous for two reasons:
     // a) They have a dangerous-looking filename
     // b) They are an extension that is not from the gallery
     if (IsDangerous(info->suggested_path.BaseName()))
       info->is_dangerous = true;
-    else if (IsChromeExtension(info->suggested_path, info->mime_type) &&
+    else if (info->mime_type == Extension::kMimeType &&
              !ExtensionsService::IsDownloadFromGallery(info->url,
                                                        info->referrer_url)) {
       info->is_dangerous = true;
     }
   }
 
   // We need to move over to the download thread because we don't want to stat
   // the suggested path on the UI thread.
   file_loop_->PostTask(FROM_HERE,
       NewRunnableMethod(this,
@@ skipping 259 matching lines @@
   if (it != dangerous_finished_.end())
     dangerous_finished_.erase(it);
 
   // Open the download if the user or user prefs indicate it should be.
   FilePath::StringType extension = download->full_path().Extension();
   // Drop the leading period. (The auto-open list is period-less.)
   if (extension.size() > 0)
     extension = extension.substr(1);
 
   // Handle chrome extensions explicitly and skip the shell execute.
-  if (IsChromeExtension(download->full_path(), download->mime_type())) {
+  if (download->mime_type() == Extension::kMimeType) {
     OpenChromeExtension(download->full_path(), download->url(),
                         download->referrer_url());
     download->set_auto_opened(true);
   } else if (download->open_when_complete() ||
              ShouldOpenFileExtension(extension)) {
     OpenDownloadInShell(download, NULL);
     download->set_auto_opened(true);
   }
 
   // Notify our observers that we are complete (the call to Finished() set the
@@ skipping 364 matching lines @@
       NewRunnableMethod(file_manager_,
                         &DownloadFileManager::OnShowDownloadInShell,
                         FilePath(download->full_path())));
 #endif
 }
 
 void DownloadManager::OpenDownload(const DownloadItem* download,
                                    gfx::NativeView parent_window) {
   // Open Chrome extensions with ExtensionsService. For everything else do shell
   // execute.
-  if (IsChromeExtension(download->full_path(), download->mime_type())) {
+  if (download->mime_type() == Extension::kMimeType) {
     OpenChromeExtension(download->full_path(), download->url(),
                         download->referrer_url());
   } else {
     OpenDownloadInShell(download, parent_window);
   }
 }
 
 void DownloadManager::OpenChromeExtension(const FilePath& full_path,
                                           const GURL& download_url,
                                           const GURL& referrer_url) {
@@ skipping 273 matching lines @@
 
   if (contents)
     contents->OnStartDownload(download);
 }
 
 // Clears the last download path, used to initialize "save as" dialogs.
 void DownloadManager::ClearLastDownloadPath() {
   last_download_path_ = FilePath();
 }