Added an option (-i) to have dump_syms output header information only.

src/common/mac/dump_syms.h

Index: src/common/mac/dump_syms.h
diff --git a/src/common/mac/dump_syms.h b/src/common/mac/dump_syms.h
index b09928c95fbc5ddbd2f550940f0e36d98e2a36ec..9463f7dc0ce529f7a8e7013061850d5c3fca4360 100644
--- a/src/common/mac/dump_syms.h
+++ b/src/common/mac/dump_syms.h
@@ -112,6 +112,11 @@ class DumpSymbols {
   // return false.
   bool WriteSymbolFile(std::ostream &stream);
 
+  // Read the selected object file's debugging information, and write out the
+  // header only to |stream|. Return true on success; if an error occurs, report
+  // it and return false.
+  bool WriteSymbolFileHeader(std::ostream &stream);
+
   // As above, but simply return the debugging information in module
   // instead of writing it to a stream. The caller owns the resulting
   // module object and must delete it when finished.
@@ -130,6 +135,10 @@ class DumpSymbols {
   // Return an identifier string for the file this DumpSymbols is dumping.
   std::string Identifier();
 
+
+  // Creates an empty module object.
+  bool CreateEmptyModule(scoped_ptr<Module>& module);
+
   // Read debugging information from |dwarf_sections|, which was taken from
   // |macho_reader|, and add it to |module|. On success, return true;
   // on failure, report the problem and return false.