title: Quota exceeded trying to create file with HTML File API
body: <p>In a packaged Chrome app, I'm trying to read from a file in the PERSISTENT storage, and create it if it doesn't exist:</p>
  
  <pre><code>window.webkitRequestFileSystem(PERSISTENT, 1024*1024, function(fileSystem) {
      fileSystem.root.getFile('file.txt', {create: true}, function(fileEntry) {
          fileEntry.file(function(file) {
              var reader = new FileReader();
              reader.onloadend = function(e) {
                  console.log(this.result);
              };
              reader.readAsText(file);
           }, errorHandler);
      }, errorHandler);
  });
  </code></pre>
  
  <p>But I'm getting <code>The operation failed because it would cause the application to exceed its storage quota.</code> error.
  TEMPORARY storage is giving me the same error.
  Is there anything I should specify in the manifest.json?</p>