Add url/ to banned_directories in clang style checker.

tools/clang/plugins/ChromeClassTester.h

Index: tools/clang/plugins/ChromeClassTester.h
diff --git a/tools/clang/plugins/ChromeClassTester.h b/tools/clang/plugins/ChromeClassTester.h
index 588ae9cae5a90fedbcc2c77ec6c19b8ea5609b6e..541341de5391d17a26db0f147c285df481c84fe5 100644
--- a/tools/clang/plugins/ChromeClassTester.h
+++ b/tools/clang/plugins/ChromeClassTester.h
@@ -16,7 +16,8 @@
 // headers to subclasses which implement CheckChromeClass().
 class ChromeClassTester : public clang::ASTConsumer {
  public:
-  explicit ChromeClassTester(clang::CompilerInstance& instance);
+  explicit ChromeClassTester(clang::CompilerInstance& instance,
+                             bool check_url_directory);
   virtual ~ChromeClassTester();
 
   // clang::ASTConsumer:
@@ -79,6 +80,9 @@ class ChromeClassTester : public clang::ASTConsumer {
 
   // List of decls to check once the current top-level decl is parsed.
   std::vector<clang::TagDecl*> pending_class_decls_;
+
+  // TODO(tfarina): Remove once url/ directory compiles without warnings.
+  bool check_url_directory_;
 };
 
 #endif  // TOOLS_CLANG_PLUGINS_CHROMECLASSTESTER_H_