[content shell] further restrict what files to open during layout tests

content/shell/shell_download_manager_delegate.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 "content/shell/shell_download_manager_delegate.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gtk/gtk.h>
 #endif
 
@@ skipping 73 matching lines @@
           &ShellDownloadManagerDelegate::GenerateFilename,
           this, download->GetId(), callback, generated_name,
           default_download_path_));
   return true;
 }
 
 bool ShellDownloadManagerDelegate::ShouldOpenDownload(
       DownloadItem* item,
       const DownloadOpenDelayedCallback& callback) {
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDumpRenderTree) &&
-      WebKitTestController::Get()->IsMainWindow(item->GetWebContents())) {
+      WebKitTestController::Get()->IsMainWindow(item->GetWebContents()) &&
+      item->GetMimeType() == "text/html") {
     WebKitTestController::Get()->OpenURL(
         net::FilePathToFileURL(item->GetFullPath()));
   }
   return true;
 }
 
 void ShellDownloadManagerDelegate::GenerateFilename(
     int32 download_id,
     const DownloadTargetCallback& callback,
     const base::FilePath& generated_name,
@@ skipping 89 matching lines @@
                DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS, result);
 }
 
 void ShellDownloadManagerDelegate::SetDownloadBehaviorForTesting(
     const base::FilePath& default_download_path) {
   default_download_path_ = default_download_path;
   suppress_prompting_ = true;
 }
 
 }  // namespace content