Make FileStream::Seek async and add FileStream::SeekSync for sync operation

webkit/blob/blob_url_request_job.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 "webkit/blob/blob_url_request_job.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ skipping 367 matching lines @@
   if (rv != base::PLATFORM_FILE_OK) {
     NotifyFailure(net::ERR_FAILED);
     return;
   }
 
   DCHECK(!stream_.get());
   stream_.reset(new net::FileStream(file.ReleaseValue(), kFileOpenFlags, NULL));
 
   const BlobData::Item& item = blob_data_->items().at(current_item_index_);
   {
-    // stream_.Seek() blocks the IO thread, see http://crbug.com/75548.
+    // stream_.SeekSync() blocks the IO thread, see http://crbug.com/75548.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     int64 offset = current_item_offset_ + static_cast<int64>(item.offset);
-    if (offset > 0 && offset != stream_->Seek(net::FROM_BEGIN, offset)) {
+    if (offset > 0 && offset != stream_->SeekSync(net::FROM_BEGIN, offset)) {
       NotifyFailure(net::ERR_FAILED);
       return;
     }
   }
 
   ReadFileStream(bytes_to_read);
 }
 
 bool BlobURLRequestJob::ReadFileStream(int bytes_to_read) {
   DCHECK(stream_.get());
@@ skipping 170 matching lines @@
   response_info_.reset(new net::HttpResponseInfo());
   response_info_->headers = headers;
 
   set_expected_content_size(remaining_bytes_);
   headers_set_ = true;
 
   NotifyHeadersComplete();
 }
 
 }  // namespace webkit_blob