Add some unit tests for Linux WriteSymbolFile

This patch adds synth_elf::{StringTable,SymbolTable,ELF} classes to
produce in-memory ELF files to properly test the Linux symbol dumping
code. It also uses those classes to add some basic tests for
the WriteSymbolFile function.

R=jimb at http://breakpad.appspot.com/277001/show

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@794 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/dwarf_line_to_module.cc

@@ -34,6 +34,8 @@
 
 #include "common/dwarf_line_to_module.h"
 
+#include <stdio.h>
+
 // Trying to support Windows paths in a reasonable way adds a lot of
 // variations to test; it would be better to just put off dealing with
 // it until we actually have to deal with DWARF on Windows.