Pass the FileAPI test suite.

[Ms2ger]

• Specification: https://w3c.github.io/FileAPI/.
• Tests: tests/wpt/web-platform-tests/FileAPI/.
• Metadata: tests/wpt/metadata/FileAPI/.
• Upstream tests: https://github.com/w3c/web-platform-tests/tree/master/FileAPI.

[izgzhen]

Checklist:

• fileReader.html (probably caused by ArrayBuffer as well):
  • FileReader States -- abort
  • FileReader States -- events
• FileReaderSync.worker.js
  • readAsText
• idlharness.worker.js
  • URL interface: operation createFor(Blob)
  • FileReader interface
    • ArrayBuffer related ones
    • readAsBinaryString
  • FileReaderSync interface
  • existence and properties of interface object:
    • Windows
    • ArrayBuffer
    • URL
    • EventTarget
• idlharness.html
  • URL interface: operation createFor(Blob)
  • FileReader interface
    • ArrayBuffer related ones
    • readAsBinaryString
  • FileReaderSync
• url_createobjecturl_blob.html
  • Check if the Blob URI starts with 'blob' using createFor()
• Determining-Encoding.html (also blocked by ArrayBuffer)
• FileReader-multiple-reads.html
  • ArrayBuffer related ones
• filereader_readAsArrayBuffer.html
• filereader_result.html
  • readAsArrayBuffer
• File-constructor.html
  • ArrayBuffer related ones
• Blob-constructor.html
  • Passing non-objects, Dates and RegExps for blobParts should throw a TypeError.
  • ArrayBuffer ones
  • Passing an platform object that supports indexed properties as the blobParts array should work (select).
  • Passing a FrozenArray as the blobParts array should work (FrozenArray).