Allow POSIX callers to specify a new file's mode.

base/files/file_util_unittest.cc

Index: base/files/file_util_unittest.cc
diff --git a/base/files/file_util_unittest.cc b/base/files/file_util_unittest.cc
index bd4839aad50771e4784594ea526900d857b2ab48..1182ed61c2026483f4d91e223d51a7df799c40cf 100644
--- a/base/files/file_util_unittest.cc
+++ b/base/files/file_util_unittest.cc
@@ -2122,6 +2122,28 @@ TEST_F(FileUtilTest, TouchFile) {
             file_info.last_modified.ToInternalValue());
 }
 
+#if defined(OS_POSIX)
+TEST_F(FileUtilTest, WriteFileMode) {
+  FilePath data_dir =
+      temp_dir_.path().Append(FILE_PATH_LITERAL("FilePathTest"));
+
+  // Create a fresh, empty copy of this directory.
+  if (PathExists(data_dir)) {
+    ASSERT_TRUE(DeleteFile(data_dir, true));
+  }
+  ASSERT_TRUE(CreateDirectory(data_dir));
+
+  FilePath foobar(data_dir.Append(FILE_PATH_LITERAL("foobar.txt")));
+  std::string data("hello");
+  mode_t mode = 0644;
+  ASSERT_TRUE(WriteFileMode(foobar, data.c_str(), data.length(), mode));
+
+  struct stat status;
+  ASSERT_EQ(0, stat(foobar.value().c_str(), &status));
+  ASSERT_EQ(mode, status.st_mode & 0777);
+}
+#endif
+
 TEST_F(FileUtilTest, IsDirectoryEmpty) {
   FilePath empty_dir = temp_dir_.path().Append(FILE_PATH_LITERAL("EmptyDir"));