Modify content::GetFontTable so clients can control what is read.

content/public/common/child_process_sandbox_support_linux.h

Index: content/public/common/child_process_sandbox_support_linux.h
diff --git a/content/public/common/child_process_sandbox_support_linux.h b/content/public/common/child_process_sandbox_support_linux.h
index 20945582c064a0c05322f1f4e695b65fae237a10..5cfe43e8b34e1ffca35974b5411e7d184ba3efaf 100644
--- a/content/public/common/child_process_sandbox_support_linux.h
+++ b/content/public/common/child_process_sandbox_support_linux.h
@@ -31,14 +31,16 @@ CONTENT_EXPORT int MatchFontWithFallback(const std::string& face, bool bold,
 
 // GetFontTable loads a specified font table from an open SFNT file.
 //   fd: a file descriptor to the SFNT file. The position doesn't matter.
-//   table: the table in *big-endian* format, or 0 for the whole font file.
+//   table: the table in *big-endian* format, or 0 for the entire font.
+//   offset: offset into the table or entire font where loading should start.
+//     The offset must be non-negative.
 //   output: a buffer of size output_length that gets the data.  can be 0, in
 //     which case output_length will be set to the required size in bytes.
 //   output_length: size of output, if it's not 0.
 //
 //   returns: true on success.
-CONTENT_EXPORT bool GetFontTable(int fd, uint32_t table, uint8_t* output,
-                                 size_t* output_length);
+CONTENT_EXPORT bool GetFontTable(int fd, uint32_t table, off_t offset,
+                                 uint8_t* output, size_t* output_length);
 
 };  // namespace content