GN: only write targets that should be generated.

tools/gn/builder.h

 // 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.
 
 #ifndef TOOLS_GN_BUILDER_H_
 #define TOOLS_GN_BUILDER_H_
 
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "tools/gn/builder_record.h"
 #include "tools/gn/label.h"
 #include "tools/gn/label_ptr.h"
 #include "tools/gn/unique_vector.h"
 
 class Config;
 class Err;
 class Loader;
 class ParseNode;
 
 // The builder assembles the dependency tree. It is not threadsafe and runs on
 // the main thread only. See also BuilderRecord.
 class Builder {
  public:
-  typedef base::Callback<void(const BuilderRecord*)> ResolvedCallback;
+  typedef base::Callback<void(const BuilderRecord*)> ResolvedGeneratedCallback;
 
   explicit Builder(Loader* loader);
   ~Builder();
 
-  // The resolved callback is called whenever a target has been resolved. This
-  // will be executed only on the main thread.
-  void set_resolved_callback(const ResolvedCallback& cb) {
-    resolved_callback_ = cb;
+  // The resolved callback is called when a target has been both resolved and
+  // marked generated. This will be executed only on the main thread.
+  void set_resolved_and_generated_callback(
+      const ResolvedGeneratedCallback& cb) {
+    resolved_and_generated_callback_ = cb;
   }
 
   Loader* loader() const { return loader_; }
 
   void ItemDefined(std::unique_ptr<Item> item);
 
   // Returns NULL if there is not a thing with the corresponding label.
   const Item* GetItem(const Label& label) const;
   const Toolchain* GetToolchain(const Label& label) const;
 
@@ skipping 81 matching lines @@
   std::string CheckForCircularDependencies(
       const std::vector<const BuilderRecord*>& bad_records) const;
 
   // Non owning pointer.
   Loader* loader_;
 
   // Owning pointers.
   typedef base::hash_map<Label, BuilderRecord*> RecordMap;
   RecordMap records_;
 
-  ResolvedCallback resolved_callback_;
+  ResolvedGeneratedCallback resolved_and_generated_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(Builder);
 };
 
 #endif  // TOOLS_GN_BUILDER_H_