[HTMLCanvasElement.toBlob] Default callback version without scheduler

Source/core/fileapi/File.h

Index: Source/core/fileapi/File.h
diff --git a/Source/core/fileapi/File.h b/Source/core/fileapi/File.h
index 68ed9ce5325f9d38f16823c846c0992985982b2a..651df2330ff5ccb577e948308ff50e7e0e5c6a6e 100644
--- a/Source/core/fileapi/File.h
+++ b/Source/core/fileapi/File.h
@@ -68,6 +68,8 @@ public:
         return new File(name, modificationTime, blobDataHandle);
     }
 
+    static File* create(char* data, size_t bytes, const String& mimeType);
+
     // For deserialization.
     static File* createFromSerialization(const String& path, const String& name, const String& relativePath, UserVisibility userVisibility, bool hasSnaphotData, uint64_t size, double lastModified, PassRefPtr<BlobDataHandle> blobDataHandle)
     {