We should download text/csv mime types instead of displaying them....

net/base/mime_util.cc

 // Copyright (c) 2006-2008 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 <string>
 
 #include "net/base/mime_util.h"
 #include "net/base/platform_mime_util.h"
 
 #include "base/hash_tables.h"
@@ skipping 224 matching lines @@
 bool MimeUtil::IsSupportedJavascriptMimeType(const char* mime_type) const {
   return javascript_map_.find(mime_type) != javascript_map_.end();
 }
 
 bool MimeUtil::IsViewSourceMimeType(const char* mime_type) const {
   return view_source_map_.find(mime_type) != view_source_map_.end();
 }
 
 // Mirrors WebViewImpl::CanShowMIMEType()
 bool MimeUtil::IsSupportedMimeType(const std::string& mime_type) const {
-  if (mime_type.compare(0, 5, "text/") == 0 ||
-      (mime_type.compare(0, 6, "image/") == 0 &&
-       IsSupportedImageMimeType(mime_type.c_str())) ||
-      IsSupportedNonImageMimeType(mime_type.c_str()))
-    return true;
-  return false;
+  return (mime_type.compare(0, 6, "image/") == 0 &&
+          IsSupportedImageMimeType(mime_type.c_str())) ||
+         IsSupportedNonImageMimeType(mime_type.c_str());
 }
 
 bool MimeUtil::MatchesMimeType(const std::string &mime_type_pattern,
                                const std::string &mime_type) const {
   // verify caller is passing lowercase
   DCHECK(mime_type_pattern == StringToLowerASCII(mime_type_pattern));
   DCHECK(mime_type == StringToLowerASCII(mime_type));
 
   // This comparison handles absolute maching and also basic
   // wildcards.  The plugin mime types could be:
@@ skipping 67 matching lines @@
   return GetMimeUtil()->IsSupportedMimeType(mime_type);
 }
 
 bool MatchesMimeType(const std::string &mime_type_pattern,
                      const std::string &mime_type) {
   return GetMimeUtil()->MatchesMimeType(mime_type_pattern, mime_type);
 }
 
 }  // namespace net