Grab bag of clang fixes for Windows code

ui/shell_dialogs/select_file_dialog_win_unittest.cc

Index: ui/shell_dialogs/select_file_dialog_win_unittest.cc
diff --git a/ui/shell_dialogs/select_file_dialog_win_unittest.cc b/ui/shell_dialogs/select_file_dialog_win_unittest.cc
index 1c0e892f61a29d1e70a7b7d9b183dc885d34f142..d9f0cd665ebc84c364e06539b6153561bce9d3b3 100644
--- a/ui/shell_dialogs/select_file_dialog_win_unittest.cc
+++ b/ui/shell_dialogs/select_file_dialog_win_unittest.cc
@@ -8,10 +8,10 @@
 
 TEST(ShellDialogsWin, AppendExtensionIfNeeded) {
   struct AppendExtensionTestCase {
-    wchar_t* filename;
-    wchar_t* filter_selected;
-    wchar_t* suggested_ext;
-    wchar_t* expected_filename;
+    const wchar_t* filename;
+    const wchar_t* filter_selected;
+    const wchar_t* suggested_ext;
+    const wchar_t* expected_filename;
   } test_cases[] = {
     // Known extensions, with or without associated MIME types, should not get
     // an extension appended.