| Index: storage/browser/blob/blob_data_builder.cc | 
| diff --git a/storage/browser/blob/blob_data_builder.cc b/storage/browser/blob/blob_data_builder.cc | 
| index 2ebfe89e454b094b5bab1b27ca80013021351831..69d9773bf7d00ce6e0c197c60c9f271e9b3de520 100644 | 
| --- a/storage/browser/blob/blob_data_builder.cc | 
| +++ b/storage/browser/blob/blob_data_builder.cc | 
| @@ -12,6 +12,9 @@ | 
|  | 
| namespace storage { | 
|  | 
| +const char BlobDataBuilder::kAppendFutureFileTemporaryFileName[] = | 
| +    "kFakeFilenameToBeChangedByPopulateFutureFile"; | 
| + | 
| BlobDataBuilder::BlobDataBuilder(const std::string& uuid) : uuid_(uuid) { | 
| } | 
| BlobDataBuilder::~BlobDataBuilder() { | 
| @@ -65,6 +68,7 @@ bool BlobDataBuilder::PopulateFutureData(size_t index, | 
| const char* data, | 
| size_t offset, | 
| size_t length) { | 
| +  DCHECK_LT(index, items_.size()); | 
| DCHECK(data); | 
| DataElement* element = items_.at(index)->data_element_ptr(); | 
|  | 
| @@ -93,6 +97,40 @@ bool BlobDataBuilder::PopulateFutureData(size_t index, | 
| return true; | 
| } | 
|  | 
| +size_t BlobDataBuilder::AppendFutureFile(uint64_t offset, uint64_t length) { | 
| +  CHECK_NE(length, 0ull); | 
| +  scoped_ptr<DataElement> element(new DataElement()); | 
| +  element->SetToFilePathRange(base::FilePath::FromUTF8Unsafe(std::string( | 
| +                                  kAppendFutureFileTemporaryFileName)), | 
| +                              offset, length, base::Time()); | 
| +  items_.push_back(new BlobDataItem(element.Pass())); | 
| +  return items_.size() - 1; | 
| +} | 
| + | 
| +bool BlobDataBuilder::PopulateFutureFile( | 
| +    size_t index, | 
| +    const scoped_refptr<ShareableFileReference>& file_reference, | 
| +    const base::Time& expected_modification_time) { | 
| +  DCHECK_LT(index, items_.size()); | 
| +  DataElement* old_element = items_.at(index)->data_element_ptr(); | 
| + | 
| +  if (old_element->type() != DataElement::TYPE_FILE) { | 
| +    DVLOG(1) << "Invalid item type."; | 
| +    return false; | 
| +  } else if (old_element->path().AsUTF8Unsafe() != | 
| +             std::string(kAppendFutureFileTemporaryFileName)) { | 
| +    DVLOG(1) << "Item not created by AppendFutureFile"; | 
| +    return false; | 
| +  } | 
| +  uint64_t length = old_element->length(); | 
| +  uint64_t offset = old_element->offset(); | 
| +  scoped_ptr<DataElement> element(new DataElement()); | 
| +  element->SetToFilePathRange(file_reference->path(), offset, length, | 
| +                              expected_modification_time); | 
| +  items_[index] = new BlobDataItem(element.Pass(), file_reference); | 
| +  return true; | 
| +} | 
| + | 
| void BlobDataBuilder::AppendFile(const base::FilePath& file_path, | 
| uint64_t offset, | 
| uint64_t length, | 
|  |