Implement File constructor.

Source/core/fileapi/BlobBuilder.h

Index: Source/core/fileapi/BlobBuilder.h
diff --git a/Source/core/fileapi/BlobBuilder.h b/Source/core/fileapi/BlobBuilder.h
index 560a79c8d1ea8825e809f2858a9aee960a176d7f..ff7013f7054be5a319f671673413a2c11216b1c0 100644
--- a/Source/core/fileapi/BlobBuilder.h
+++ b/Source/core/fileapi/BlobBuilder.h
@@ -34,15 +34,10 @@
 #include "platform/blob/BlobData.h"
 #include "wtf/Forward.h"
 
-namespace WTF{
-class TextEncoding;
-}
-
 namespace WebCore {
 
 class Blob;
-
-typedef int ExceptionCode;
+class File;
 
 class BlobBuilder {
 public:
@@ -54,6 +49,7 @@ public:
     void append(ArrayBufferView*);
 
     PassRefPtr<Blob> getBlob(const String& contentType);
+    PassRefPtr<File> getFile(const String& contentType, const String& fileName, double modificationTime);
 
 private:
     void appendBytesData(const void*, size_t);