drive: Fix a crash in gdata::DriveUploader::ResumeUpload()

chrome/browser/chromeos/drive/drive_uploader.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 "chrome/browser/chromeos/drive/drive_uploader.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 399 matching lines @@
                  bytes_to_read));
 }
 
 void DriveUploader::ReadCompletionCallback(
     int upload_id,
     int bytes_to_read,
     int bytes_read) {
   // The Read is asynchronously executed on BrowserThread::UI, where
   // Read() was called.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  // Should be non-zero. FileStream::Read() returns 0 only at end-of-file,
+  // but we don't try to read from end-of-file.
+  DCHECK_NE(0, bytes_read);
   DVLOG(1) << "ReadCompletionCallback bytes read=" << bytes_read;
 
   UploadFileInfo* upload_file_info = GetUploadFileInfo(upload_id);
   if (!upload_file_info)
     return;
 
-  // TODO(achuith): Handle this error.
-  DCHECK_EQ(bytes_to_read, bytes_read);
-  DCHECK_GT(bytes_read, 0) << "Error reading from file "
-                           << upload_file_info->file_path.value();
+  if (bytes_read < 0) {
+    LOG(ERROR) << "Error reading from file "
+               << upload_file_info->file_path.value();
+    UploadFailed(upload_file_info, google_apis::DRIVE_UPLOAD_ERROR_ABORT);
+    return;
+  }
 
   upload_file_info->start_range = upload_file_info->end_range + 1;
   upload_file_info->end_range = upload_file_info->start_range +
                                 bytes_read - 1;
 
   ResumeUpload(upload_id);
 }
 
 void DriveUploader::ResumeUpload(int upload_id) {
   UploadFileInfo* upload_file_info = GetUploadFileInfo(upload_id);
@@ skipping 125 matching lines @@
   return "title=[" + title +
          "], file_path=[" + file_path.AsUTF8Unsafe() +
          "], content_type=[" + content_type +
          "], content_length=[" + base::UintToString(content_length) +
          "], file_size=[" + base::UintToString(file_size) +
          "], drive_path=[" + drive_path.AsUTF8Unsafe() +
          "]";
 }
 
 }  // namespace drive