Add an assert_no_deps variable to GN.

tools/gn/variables.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_GN_VARIABLES_H_
 #define TOOLS_GN_VARIABLES_H_
 
 #include <map>
 
 #include "base/strings/string_piece.h"
@@ skipping 69 matching lines @@
 extern const char kAllowCircularIncludesFrom_Help[];
 
 extern const char kArgs[];
 extern const char kArgs_HelpShort[];
 extern const char kArgs_Help[];
 
 extern const char kAsmflags[];
 extern const char kAsmflags_HelpShort[];
 extern const char* kAsmflags_Help;
 
+extern const char kAssertNoDeps[];
+extern const char kAssertNoDeps_HelpShort[];
+extern const char kAssertNoDeps_Help[];
+
 extern const char kCflags[];
 extern const char kCflags_HelpShort[];
 extern const char* kCflags_Help;
 
 extern const char kCflagsC[];
 extern const char kCflagsC_HelpShort[];
 extern const char* kCflagsC_Help;
 
 extern const char kCflagsCC[];
 extern const char kCflagsCC_HelpShort[];
@@ skipping 132 matching lines @@
 // Note: this is used only for help so this getter is not threadsafe.
 const VariableInfoMap& GetBuiltinVariables();
 
 // Returns the variables used by target generators.
 // Note: this is used only for help so this getter is not threadsafe.
 const VariableInfoMap& GetTargetVariables();
 
 }  // namespace variables
 
 #endif  // TOOLS_GN_VARIABLES_H_