Add an optional root prefix to Linux dumpers

src/client/linux/minidump_writer/minidump_writer.cc

 // Copyright (c) 2010, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 549 matching lines @@
     } else {
       // Note: ElfFileIdentifierForMapping() can manipulate the |mapping.name|.
       dumper_->ElfFileIdentifierForMapping(mapping, member,
                                            mapping_id, signature);
     }
     my_memset(cv_ptr, 0, sizeof(uint32_t));  // Set age to 0 on Linux.
     cv_ptr += sizeof(uint32_t);
 
     char file_name[NAME_MAX];
     char file_path[NAME_MAX];
-    LinuxDumper::GetMappingEffectiveNameAndPath(
+    dumper_->GetMappingEffectiveNameAndPath(
         mapping, file_path, sizeof(file_path), file_name, sizeof(file_name));
 
     const size_t file_name_len = my_strlen(file_name);
     UntypedMDRVA cv(&minidump_writer_);
     if (!cv.Allocate(MDCVInfoPDB70_minsize + file_name_len + 1))
       return false;
 
     // Write pdb_file_name
     my_memcpy(cv_ptr, file_name, file_name_len + 1);
     cv.Copy(cv_buf, MDCVInfoPDB70_minsize + file_name_len + 1);
@@ skipping 777 matching lines @@
                    const MappingList& mappings,
                    const AppMemoryList& appmem,
                    LinuxDumper* dumper) {
   MinidumpWriter writer(filename, -1, NULL, mappings, appmem, dumper);
   if (!writer.Init())
     return false;
   return writer.Dump();
 }
 
 }  // namespace google_breakpad