Have media gallery (through native media file util) use MIME sniffer

net/base/mime_sniffer.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_BASE_MIME_SNIFFER_H__
 #define NET_BASE_MIME_SNIFFER_H__
 
 #include <string>
 
 #include "net/base/net_export.h"
@@ skipping 23 matching lines @@
 // @param content A buffer containing the bytes to sniff.
 // @param content_size The number of bytes in the |content| buffer.
 // @param url The URL from which we obtained this content.
 // @param type_hint The current mime type, e.g. from the Content-Type header.
 // @param result Address at which to place the sniffed mime type.
 // @return Returns true if we have enough content to guess the mime type.
 NET_EXPORT bool SniffMimeType(const char* content, size_t content_size,
                               const GURL& url, const std::string& type_hint,
                               std::string* result);
 
+// Attempt to identify a MIME type from the first few bytes of content only.
+// Uses a bigger set of media file searches than |SniffMimeType()|.
+// If finds a match, fills in |result| and returns true,
+// otherwise returns false.
+//
+// The caller should understand the security ramifications of trusting
+// uncontrolled data before accepting the results of this function.
+//
+// @param content A buffer containing the bytes to sniff.
+// @param content_size The number of bytes in the |content| buffer.
+// @param result Address at which to place the sniffed mime type.
+// @return Returns true if a MIME type match was found.
+NET_EXPORT bool SniffMimeTypeFromLocalData(const char* content,
+                                           size_t content_size,
+                                           std::string* result);
+
 }  // namespace net
 
 #endif  // NET_BASE_MIME_SNIFFER_H__