Add arflags to GN

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 42 matching lines @@
 
   // Valid for linker tools.
   SUBSTITUTION_LINKER_INPUTS,  // {{inputs}}
   SUBSTITUTION_LINKER_INPUTS_NEWLINE,  // {{inputs_newline}}
   SUBSTITUTION_LDFLAGS,  // {{ldflags}}
   SUBSTITUTION_LIBS,  // {{libs}}
   SUBSTITUTION_OUTPUT_DIR,  // {{output_dir}}
   SUBSTITUTION_OUTPUT_EXTENSION,  // {{output_extension}}
   SUBSTITUTION_SOLIBS,  // {{solibs}}
 
+  // Valid for alink only.
+  SUBSTITUTION_ARFLAGS,  // {{arflags}}
+
   // Valid for bundle_data targets.
   SUBSTITUTION_BUNDLE_ROOT_DIR,  // {{bundle_root_dir}}
   SUBSTITUTION_BUNDLE_RESOURCES_DIR,  // {{bundle_resources_dir}}
   SUBSTITUTION_BUNDLE_EXECUTABLE_DIR,  // {{bundle_executable_dir}}
   SUBSTITUTION_BUNDLE_PLUGINS_DIR,  // {{bundle_plugins_dir}}
 
   // Used only for the args of actions.
   SUBSTITUTION_RSP_FILE_NAME,  // {{response_file_name}}
 
   SUBSTITUTION_NUM_TYPES  // Must be last.
@@ skipping 37 matching lines @@
 
 // Returns true if the given substitution is valid for the named purpose.
 bool IsValidBundleDataSubstitution(SubstitutionType type);
 bool IsValidSourceSubstitution(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(
     const std::vector<SubstitutionType>& types,
     const ParseNode* origin,
     Err* err);
 
 #endif  // TOOLS_GN_SUBSTITUTION_TYPE_H_