Convert some tools to use FilePaths for file names.

chrome/tools/convert_dict/dic_reader.h

Index: chrome/tools/convert_dict/dic_reader.h
diff --git a/chrome/tools/convert_dict/dic_reader.h b/chrome/tools/convert_dict/dic_reader.h
index efb06a73a8db4c36d514ae74cdbd40b932da7e89..4e63ae4f9644b0ef9404408fab4c8ad5902d2e6c 100644
--- a/chrome/tools/convert_dict/dic_reader.h
+++ b/chrome/tools/convert_dict/dic_reader.h
@@ -10,6 +10,8 @@
 #include <string>
 #include <vector>
 
+class FilePath;
+
 namespace convert_dict {
 
 class AffReader;
@@ -23,7 +25,7 @@ class DicReader {
   typedef std::pair<std::string, std::vector<int> > WordEntry;
   typedef std::vector<WordEntry> WordList;
 
-  explicit DicReader(const std::string& filename);
+  explicit DicReader(const FilePath& path);
   ~DicReader();
 
   // Non-numeric affixes will be added to the given AffReader and converted into