Move more code to using FilePath.

base/base_paths_mac.mm

Index: base/base_paths_mac.mm
diff --git a/base/base_paths_mac.mm b/base/base_paths_mac.mm
index b9830513e1e4014469876184668cbc64cc108219..5dbbe30751e2cf6d7858c33718461a7ffa425fa1 100644
--- a/base/base_paths_mac.mm
+++ b/base/base_paths_mac.mm
@@ -13,7 +13,7 @@
 
 namespace base {
 
-bool PathProviderMac(int key, std::wstring* result) {
+bool PathProviderMac(int key, FilePath* result) {
   std::wstring cur;
   switch (key) {
     case base::FILE_EXE:
@@ -49,7 +49,7 @@ bool PathProviderMac(int key, std::wstring* result) {
       return false;
   }
 
-  result->swap(cur);
+  *result = FilePath::FromWStringHack(cur);
   return true;
 }