Add an output_dir override to GN.

tools/gn/substitution_type.cc

 // 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.
 
 #include "tools/gn/substitution_type.h"
 
 #include <stddef.h>
 #include <stdlib.h>
 
 #include "tools/gn/err.h"
@@ skipping 25 matching lines @@
   "{{cflags_cc}}",  // SUBSTITUTION_CFLAGS_CC
   "{{cflags_objc}}",  // SUBSTITUTION_CFLAGS_OBJC
   "{{cflags_objcc}}",  // SUBSTITUTION_CFLAGS_OBJCC
   "{{defines}}",  // SUBSTITUTION_DEFINES
   "{{include_dirs}}",  // SUBSTITUTION_INCLUDE_DIRS
 
   "{{inputs}}",  // SUBSTITUTION_LINKER_INPUTS
   "{{inputs_newline}}",  // SUBSTITUTION_LINKER_INPUTS_NEWLINE
   "{{ldflags}}",  // SUBSTITUTION_LDFLAGS
   "{{libs}}",  // SUBSTITUTION_LIBS
+  "{{output_dir}}",  // SUBSTITUTION_OUTPUT_DIR
   "{{output_extension}}",  // SUBSTITUTION_OUTPUT_EXTENSION
   "{{solibs}}",  // SUBSTITUTION_SOLIBS
 
   "{{bundle_root_dir}}",  // SUBSTITUTION_BUNDLE_ROOT_DIR
   "{{bundle_resources_dir}}",  // SUBSTITUTION_BUNDLE_RESOURCES_DIR
   "{{bundle_executable_dir}}",  // SUBSTITUTION_BUNDLE_EXECUTABLE_DIR
   "{{bundle_plugins_dir}}",  // SUBSTITUTION_BUNDLE_PLUGINS_DIR
 
   "{{response_file_name}}",  // SUBSTITUTION_RSP_FILE_NAME
 };
@@ skipping 28 matching lines @@
     "defines",       // SUBSTITUTION_DEFINES
     "include_dirs",  // SUBSTITUTION_INCLUDE_DIRS
 
     // LINKER_INPUTS expands to the same Ninja var as SUBSTITUTION_SOURCE. These
     // are used in different contexts and are named differently to keep things
     // clear, but they both expand to the "set of input files" for a build rule.
     "in",                // SUBSTITUTION_LINKER_INPUTS
     "in_newline",        // SUBSTITUTION_LINKER_INPUTS_NEWLINE
     "ldflags",           // SUBSTITUTION_LDFLAGS
     "libs",              // SUBSTITUTION_LIBS
+    "output_dir",        // SUBSTITUTION_OUTPUT_DIR
     "output_extension",  // SUBSTITUTION_OUTPUT_EXTENSION
     "solibs",            // SUBSTITUTION_SOLIBS
 
     "bundle_root_dir",        // SUBSTITUTION_BUNDLE_ROOT_DIR
     "bundle_resources_dir",   // SUBSTITUTION_BUNDLE_RESOURCES_DIR
     "bundle_executable_dir",  // SUBSTITUTION_BUNDLE_EXECUTABLE_DIR
     "bundle_plugins_dir",     // SUBSTITUTION_BUNDLE_PLUGINS_DIR
 
     "rspfile",  // SUBSTITUTION_RSP_FILE_NAME
 };
@@ skipping 82 matching lines @@
   return (IsValidToolSubstitution(type) && type != SUBSTITUTION_OUTPUT) ||
          IsValidSourceSubstitution(type);
 }
 
 bool IsValidLinkerSubstitution(SubstitutionType type) {
   return IsValidToolSubstitution(type) ||
          type == SUBSTITUTION_LINKER_INPUTS ||
          type == SUBSTITUTION_LINKER_INPUTS_NEWLINE ||
          type == SUBSTITUTION_LDFLAGS ||
          type == SUBSTITUTION_LIBS ||
+         type == SUBSTITUTION_OUTPUT_DIR ||
          type == SUBSTITUTION_OUTPUT_EXTENSION ||
          type == SUBSTITUTION_SOLIBS;
 }
 
 bool IsValidLinkerOutputsSubstitution(SubstitutionType type) {
   // All valid compiler outputs plus the output extension.
   return IsValidCompilerOutputsSubstitution(type) ||
+         type == SUBSTITUTION_OUTPUT_DIR ||
          type == SUBSTITUTION_OUTPUT_EXTENSION;
 }
 
 bool IsValidCopySubstitution(SubstitutionType type) {
   return IsValidToolSubstitution(type) ||
          type == SUBSTITUTION_SOURCE;
 }
 
 bool IsValidCompileXCassetsSubstitution(SubstitutionType type) {
   return IsValidToolSubstitution(type) ||
          type == SUBSTITUTION_LINKER_INPUTS;
 }
 
 bool EnsureValidSourcesSubstitutions(
     const std::vector<SubstitutionType>& types,
     const ParseNode* origin,
     Err* err) {
   for (size_t i = 0; i < types.size(); i++) {
     if (!IsValidSourceSubstitution(types[i])) {
       *err = Err(origin, "Invalid substitution type.",
           "The substitution " + std::string(kSubstitutionNames[types[i]]) +
           " isn't valid for something\n"
           "operating on a source file such as this.");
       return false;
     }
   }
   return true;
 }