Fix a bug in file_util::Delete() where symlinks are not handled right

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index 1eac1caa9975e3f2247859a9dfce562e3a46de21..53eefcc4de1f2a71bb316a44bf97240dd70052dc 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -100,6 +100,9 @@ BASE_EXPORT int64 ComputeFilesSize(const FilePath& directory,
 // subdirectories and their contents as well.
 // Returns true if successful, false otherwise.
 //
+// In posix environment and if |path| is a symbolic link, this deletes only
+// the symlink. (even if the symlink deferences to a non-existent file)
+//
 // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
 //          TO "rm -rf", SO USE WITH CAUTION.
 BASE_EXPORT bool Delete(const FilePath& path, bool recursive);