Files.app: Enable externalfile: protocol for MTP volumes.

chrome/browser/chromeos/file_manager/filesystem_api_util.cc

 // Copyright 2014 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/chromeos/file_manager/filesystem_api_util.h"
 
 #include "base/callback.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 17 matching lines @@
 namespace {
 
 // Helper function used to implement GetNonNativeLocalPathMimeType. It extracts
 // the mime type from the passed Drive resource entry.
 void GetMimeTypeAfterGetResourceEntryForDrive(
     const base::Callback<void(bool, const std::string&)>& callback,
     drive::FileError error,
     scoped_ptr<drive::ResourceEntry> entry) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
-  if (error != drive::FILE_ERROR_OK || !entry->has_file_specific_info()) {
+  if (error != drive::FILE_ERROR_OK || !entry->has_file_specific_info() ||
+      entry->file_specific_info().content_mime_type().empty()) {

[mtomasz, 2014/09/25 06:48:09]

Could you please extract it into a separate CL? This is a serious bug.

[hirono, 2014/09/25 07:38:07]

I got it. Let me separate.

     callback.Run(false, std::string());
     return;
   }
   callback.Run(true, entry->file_specific_info().content_mime_type());
 }
 
 // Helper function used to implement GetNonNativeLocalPathMimeType. It extracts
 // the mime type from the passed metadata from a providing extension.
 void GetMimeTypeAfterGetMetadataForProvidedFileSystem(
     const base::Callback<void(bool, const std::string&)>& callback,
     scoped_ptr<chromeos::file_system_provider::EntryMetadata> metadata,
     base::File::Error result) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
-  if (result != base::File::FILE_OK) {
+  if (result != base::File::FILE_OK || metadata->mime_type.empty()) {
     callback.Run(false, std::string());
     return;
   }
   callback.Run(true, metadata->mime_type);
 }
 
 // Helper function to converts a callback that takes boolean value to that takes
 // File::Error, by regarding FILE_OK as the only successful value.
 void BoolCallbackAsFileErrorCallback(
     const base::Callback<void(bool)>& callback,
@@ skipping 106 matching lines @@
 
     parser.file_system()->GetMetadata(
         parser.file_path(),
         chromeos::file_system_provider::ProvidedFileSystemInterface::
             METADATA_FIELD_DEFAULT,
         base::Bind(&GetMimeTypeAfterGetMetadataForProvidedFileSystem,
                    callback));
     return;
   }
 
-  // As a fallback just return success with an empty mime type value.
+  // As a fallback just return failure with an empty mime type value.

[mtomasz, 2014/09/25 06:48:09]

nit: The comment doesn't make much sense anymore. Fallback is usually some
alternative solution, but we just clearly return an error, so maybe the word
"fallback" is confusing here?

[hirono, 2014/09/25 07:38:07]

Let me handle this in the extracted patch.

   content::BrowserThread::PostTask(
       content::BrowserThread::UI,
       FROM_HERE,
-      base::Bind(callback, true /* success */, std::string()));
+      base::Bind(callback, false /* failure */, std::string()));
 }
 
 void IsNonNativeLocalPathDirectory(
     Profile* profile,
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   DCHECK(IsUnderNonNativeLocalPath(profile, path));
 
   GURL url;
@@ skipping 43 matching lines @@
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(&PrepareFileOnIOThread,
                  make_scoped_refptr(context),
                  context->CrackURL(url),
                  google_apis::CreateRelayCallback(callback)));
 }
 
 }  // namespace util
 }  // namespace file_manager