tools/gn: Remove code for forward_dependent_configs_from variable.

tools/gn/functions.cc

 // 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.
 
 #include "tools/gn/functions.h"
 
 #include <iostream>
 
 #include "base/environment.h"
 #include "base/strings/string_util.h"
@@ skipping 247 matching lines @@
     "   2. The configs specified in the target's \"configs\" list, in order.\n"
     "   3. Public_configs from a breadth-first traversal of the dependency\n"
     "      tree in the order that the targets appear in \"deps\".\n"
     "   4. All dependent configs from a breadth-first traversal of the\n"
     "      dependency tree in the order that the targets appear in \"deps\".\n"
     "\n"
     "Variables valid in a config definition:\n"
     CONFIG_VALUES_VARS_HELP
     "\n"
     "Variables on a target used to apply configs:\n"
-    "  all_dependent_configs, configs, public_configs,\n"
-    "  forward_dependent_configs_from\n"
+    "  all_dependent_configs, configs, public_configs\n"
     "\n"
     "Example:\n"
     "  config(\"myconfig\") {\n"
     "    includes = [ \"include/common\" ]\n"
     "    defines = [ \"ENABLE_DOOM_MELON\" ]\n"
     "  }\n"
     "\n"
     "  executable(\"mything\") {\n"
     "    configs = [ \":myconfig\" ]\n"
     "  }\n";
@@ skipping 594 matching lines @@
   }
 
   // Otherwise it's a no-block function.
   if (!VerifyNoBlockForFunctionCall(function, block, err))
     return Value();
   return found_function->second.no_block_runner(scope, function,
                                                 args.list_value(), err);
 }
 
 }  // namespace functions