Don't print warning for unused default args

We will still produce an error if --fail-on-unused-args is used.

Bug: 684096
Change-Id: I4a0640ad83072750d555c8de9e6391f76942ae38
Reviewed-on: https://chromium-review.googlesource.com/792606
Commit-Queue: Petr Hosek <phosek@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Brett Wilson <brettw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523254}

tools/gn/args.cc

@@ -126,6 +126,12 @@ void Args::AddArgOverrides(const Scope::KeyValueMap& overrides) {
   }
 }
 
+void Args::AddDefaultArgOverrides(const Scope::KeyValueMap& overrides) {
+  base::AutoLock lock(lock_);
+  for (const auto& cur_override : overrides)
+    overrides_[cur_override.first] = cur_override.second;
+}
+
 const Value* Args::GetArgOverride(const char* name) const {
   base::AutoLock lock(lock_);
 

tools/gn/args.h

@@ -46,6 +46,10 @@ class Args {
   void AddArgOverride(const char* name, const Value& value);
   void AddArgOverrides(const Scope::KeyValueMap& overrides);
 
+  // Specifies default overrides of the build arguments. These are normally
+  // specified in the .gn file.
+  void AddDefaultArgOverrides(const Scope::KeyValueMap& overrides);
+
   // Returns the value corresponding to the given argument name, or NULL if no
   // argument is set.
   const Value* GetArgOverride(const char* name) const;

tools/gn/setup.cc

@@ -325,7 +325,7 @@ bool Setup::DoSetup(const std::string& build_dir, bool force_create) {
   if (default_args_) {
     Scope::KeyValueMap overrides;
     default_args_->GetCurrentScopeValues(&overrides);
-    build_settings_.build_args().AddArgOverrides(overrides);
+    build_settings_.build_args().AddDefaultArgOverrides(overrides);
   }
 
   if (fill_arguments_) {