Remove FileError interface

third_party/WebKit/Source/core/fileapi/FileError.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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef FileError_h
 #define FileError_h
 
-#include "bindings/core/v8/ScriptWrappable.h"
 #include "core/CoreExport.h"
-#include "core/dom/DOMError.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
+class DOMException;
 class ExceptionState;
 
-class CORE_EXPORT FileError final : public DOMError {
-    DEFINE_WRAPPERTYPEINFO();
+// A FileError holds a return code (success or failure) from a FileAPI
+// or File System operation.
+//
+// FileError used to be a subclass of DOMError exposed via IDL to script,
+// but DOMException is now used instead, with instances created lazily
+// when thrown (from synchronous APIs) or assigned as `error` members
+// or passed to callbacks (for asynchronous APIs).
+//
+// TODO(jsbell): Eliminate this class, as it contains just one member.

[foolip, 2016/06/08 10:04:44]

What would it take to actually remove it?

+class CORE_EXPORT FileError final : public GarbageCollected<FileError> {

[foolip, 2016/06/08 10:04:44]

Why does this need to be on the Oilpan heap? Can't it just be a simple copyable
type?

 public:
     enum ErrorCode {
         OK = 0,
         NOT_FOUND_ERR = 1,
         SECURITY_ERR = 2,
         ABORT_ERR = 3,
         NOT_READABLE_ERR = 4,
         ENCODING_ERR = 5,
         NO_MODIFICATION_ALLOWED_ERR = 6,
         INVALID_STATE_ERR = 7,
@@ skipping 16 matching lines @@
     static const char syntaxErrorMessage[];
     static const char typeMismatchErrorMessage[];
 
     static FileError* create(ErrorCode code)
     {
         return new FileError(code);
     }
 
     ErrorCode code() const { return m_code; }
 
+    DEFINE_INLINE_TRACE() { }
+
     static void throwDOMException(ExceptionState&, ErrorCode);
+    static DOMException* createDOMException(ErrorCode);
 
 private:
     explicit FileError(ErrorCode);
 
     ErrorCode m_code;
 };
 
 } // namespace blink
 
 #endif // FileError_h