tools/gn: Remove code for forward_dependent_configs_from variable.

tools/gn/builder.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/builder.h"
 
 #include "tools/gn/config.h"
 #include "tools/gn/deps_iterator.h"
 #include "tools/gn/err.h"
 #include "tools/gn/loader.h"
@@ skipping 463 matching lines @@
       return false;
     const_cast<LabelConfigPair&>(cur).ptr = record->item()->AsConfig();
   }
   return true;
 }
 
 // "Forward dependent configs" should refer to targets in the deps that should
 // have their configs forwarded.
 bool Builder::ResolveForwardDependentConfigs(Target* target, Err* err) {
   const UniqueVector<LabelTargetPair>& configs =
       target->forward_dependent_configs();

[brettw, 2015/10/05 18:06:06]

Is this patch trying to remove all the code for forward_dependent_configs? In
that case, I think this whole Builder::ResolveForwardDependentConfigs function,
and the Target::forward_dependent_configs stuff can all be deleted.

[tfarina, 2015/10/06 03:28:50]

Done.

 
   // Assume that the lists are small so that brute-force n^2 is appropriate.
   for (const auto& config : configs) {
     for (const auto& dep_pair : target->GetDeps(Target::DEPS_LINKED)) {
       if (config.label == dep_pair.label) {
         DCHECK(dep_pair.ptr);  // Should already be resolved.
         // UniqueVector's contents are constant so uniqueness is preserved, but
         // we want to update this pointer which doesn't change uniqueness
         // (uniqueness in this vector is determined by the label only).
         const_cast<LabelTargetPair&>(config).ptr = dep_pair.ptr;
         break;
       }
     }
-    if (!config.ptr) {
-      *err = Err(target->defined_from(),
-          "Target in forward_dependent_configs_from was not listed in the deps",
-          "This target has a forward_dependent_configs_from entry that was "
-          "not present in\nthe deps. A target can only forward things it "
-          "depends on. It was forwarding:\n  " +
-          config.label.GetUserVisibleName(false));
-      return false;
-    }
   }
   return true;
 }
 
 bool Builder::ResolveToolchain(Target* target, Err* err) {
   BuilderRecord* record = GetResolvedRecordOfType(
       target->settings()->toolchain_label(), target->defined_from(),
       BuilderRecord::ITEM_TOOLCHAIN, err);
   if (!record) {
     *err = Err(target->defined_from(),
@@ skipping 18 matching lines @@
   std::string ret;
   for (size_t i = 0; i < cycle.size(); i++) {
     ret += "  " + cycle[i]->label().GetUserVisibleName(false);
     if (i != cycle.size() - 1)
       ret += " ->";
     ret += "\n";
   }
 
   return ret;
 }