Disable "using base::FilePath" on Linux since it now compiles.

base/file_util_mac.mm

Index: base/file_util_mac.mm
diff --git a/base/file_util_mac.mm b/base/file_util_mac.mm
index 2499f442c5c5d8df861c7ae0e164a18eb4812e5f..0de378653ce5f6f63b38a1e0409bc425cfa0433f 100644
--- a/base/file_util_mac.mm
+++ b/base/file_util_mac.mm
@@ -15,7 +15,7 @@
 
 namespace file_util {
 
-bool GetTempDir(FilePath* path) {
+bool GetTempDir(base::FilePath* path) {
   NSString* tmp = NSTemporaryDirectory();
   if (tmp == nil)
     return false;
@@ -23,11 +23,12 @@ bool GetTempDir(FilePath* path) {
   return true;
 }
 
-bool GetShmemTempDir(FilePath* path, bool executable) {
+bool GetShmemTempDir(base::FilePath* path, bool executable) {
   return GetTempDir(path);
 }
 
-bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
+bool CopyFileUnsafe(const base::FilePath& from_path,
+                    const base::FilePath& to_path) {
   base::ThreadRestrictions::AssertIOAllowed();
   return (copyfile(from_path.value().c_str(),
                    to_path.value().c_str(), NULL, COPYFILE_ALL) == 0);