Validate GN substitutions in args and rsp files.

tools/gn/substitution_type.h

 // Copyright 2014 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_SUBSTITUTION_TYPE_H_
 #define TOOLS_GN_SUBSTITUTION_TYPE_H_
 
 #include <vector>
 
 class Err;
@@ skipping 100 matching lines @@
 bool SubstitutionIsInOutputDir(SubstitutionType type);
 
 // Returns true if the given substitution pattern references the bundle
 // directory. This is used to check strings that begin with a substitution to
 // verify that they produce a file in the bundle directory.
 bool SubstitutionIsInBundleDir(SubstitutionType type);
 
 // Returns true if the given substitution is valid for the named purpose.
 bool IsValidBundleDataSubstitution(SubstitutionType type);
 bool IsValidSourceSubstitution(SubstitutionType type);
+bool IsValidScriptArgsSubstitution(SubstitutionType type);
+
 // Both compiler and linker tools.
 bool IsValidToolSubstitution(SubstitutionType type);
 bool IsValidCompilerSubstitution(SubstitutionType type);
 bool IsValidCompilerOutputsSubstitution(SubstitutionType type);
 bool IsValidLinkerSubstitution(SubstitutionType type);
 bool IsValidLinkerOutputsSubstitution(SubstitutionType type);
 bool IsValidALinkSubstitution(SubstitutionType type);
 bool IsValidCopySubstitution(SubstitutionType type);
 bool IsValidCompileXCassetsSubstitution(SubstitutionType type);
 
-// Like the "IsValid..." version above but checks a list of types and sets a
-// an error blaming the given source if the test fails.
-bool EnsureValidSourcesSubstitutions(
+// Validates that each substitution type in the vector passes the given
+// is_valid_subst predicate. Returns true on success. On failure, fills in the
+// error object with an appropriate message and returns false.
+bool EnsureValidSubstitutions(
     const std::vector<SubstitutionType>& types,
+    bool (*is_valid_subst)(SubstitutionType),
     const ParseNode* origin,
     Err* err);
 
 #endif  // TOOLS_GN_SUBSTITUTION_TYPE_H_