Add cc/ to banned_directories in chromium clang style checker

tools/clang/plugins/ChromeClassTester.cpp

Index: tools/clang/plugins/ChromeClassTester.cpp
diff --git a/tools/clang/plugins/ChromeClassTester.cpp b/tools/clang/plugins/ChromeClassTester.cpp
index c61271b1b93f96929c6309dee2263acee770c72b..f32fbf108e7bc799495c069386ac18eb754f32a0 100644
--- a/tools/clang/plugins/ChromeClassTester.cpp
+++ b/tools/clang/plugins/ChromeClassTester.cpp
@@ -37,10 +37,12 @@ bool ends_with(const std::string& one, const std::string& two) {
 }  // namespace
 
 ChromeClassTester::ChromeClassTester(CompilerInstance& instance,
-                                     bool check_inner_classes)
+                                     bool check_inner_classes,
+                                     bool check_cc_directory)
     : instance_(instance),
       diagnostic_(instance.getDiagnostics()),
-      check_inner_classes_(check_inner_classes) {
+      check_inner_classes_(check_inner_classes),
+      check_cc_directory_(check_cc_directory) {
   BuildBannedLists();
 }
 
@@ -163,6 +165,9 @@ void ChromeClassTester::BuildBannedLists() {
   banned_directories_.push_back("icu4c/");
   banned_directories_.push_back("frameworks/");
 
+  if (!check_cc_directory_)
+    banned_directories_.push_back("cc/");
+
   // Don't check autogenerated headers.
   // Make puts them below $(builddir_name)/.../gen and geni.
   // Ninja puts them below OUTPUT_DIR/.../gen