Blob/File constructors/slice method shouldn't throw on invalid types

third_party/WebKit/Source/core/fileapi/Blob.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 113 matching lines @@
   explicit Blob(PassRefPtr<BlobDataHandle>);
 
   static void populateBlobData(
       BlobData*,
       const HeapVector<ArrayBufferOrArrayBufferViewOrBlobOrUSVString>& parts,
       bool normalizeLineEndingsToNative);
   static void clampSliceOffsets(long long size,
                                 long long& start,
                                 long long& end);
 
+  // Returns "" if |type| contains any character outside U+0020...U+007E, or
+  // |type| ASCII-lowercased otherwise.

[kinuko, 2017/03/08 06:13:39]

Could we make this comment a little clearer why we do this? (E.g. to make the
behavior match with what other browsers do)

[jsbell, 2017/03/10 01:04:35]

Done. Well, I referenced the spec, since this is used by the constructor
implementations to conform to the spec.

+  static String normalizeType(const String& type);
+
  private:
   Blob();
 
   RefPtr<BlobDataHandle> m_blobDataHandle;
   bool m_isClosed;
 };
 
 }  // namespace blink
 
 #endif  // Blob_h