Add not_needed function

tools/gn/scope.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_SCOPE_H_
 #define TOOLS_GN_SCOPE_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 186 matching lines @@
   void RemovePrivateIdentifiers();
 
   // Templates associated with this scope. A template can only be set once, so
   // AddTemplate will fail and return false if a rule with that name already
   // exists. GetTemplate returns NULL if the rule doesn't exist, and it will
   // check all containing scoped rescursively.
   bool AddTemplate(const std::string& name, const Template* templ);
   const Template* GetTemplate(const std::string& name) const;
 
   // Marks the given identifier as (un)used in the current scope.
-  void MarkUsed(const base::StringPiece& ident);
-  void MarkAllUsed();
+  void MarkUsed(const base::StringPiece& ident, Err* err);
+  void MarkAllUsed(Err* err);
   void MarkUnused(const base::StringPiece& ident);
 
+  // Marks the given identifier as unusable in the current scope.
+  void MarkAllUnusable(Err* err, std::set<std::string> excluded_values);

[brettw, 2017/06/20 17:27:25]

The set should be passed by const ref.

[Petr Hosek, 2017/06/21 02:17:40]

Done.

+  void MarkUnusable(const base::StringPiece& ident, Err* err);
+
   // Checks to see if the scope has a var set that hasn't been used. This is
   // called before replacing the var with a different one. It does not check
   // containing scopes.
   //
   // If the identifier is present but hasnn't been used, return true.
   bool IsSetButUnused(const base::StringPiece& ident) const;
 
   // Checks the scope to see if any values were set but not used, and fills in
   // the error and returns false if they were.
   bool CheckForUnusedVars(Err* err) const;
@@ skipping 92 matching lines @@
   // Getting a property recursively searches all scopes, and the optional
   // |found_on_scope| variable will be filled with the actual scope containing
   // the key (if the pointer is non-NULL).
   void SetProperty(const void* key, void* value);
   void* GetProperty(const void* key, const Scope** found_on_scope) const;
 
  private:
   friend class ProgrammaticProvider;
 
   struct Record {
-    Record() : used(false) {}
-    explicit Record(const Value& v) : used(false), value(v) {}
+    Record() : used(false), unusable(false) {}
+    explicit Record(const Value& v) : used(false), unusable(false), value(v) {}
 
     bool used;  // Set to true when the variable is used.
+    bool unusable;
     Value value;
   };
 
   typedef base::hash_map<base::StringPiece, Record, base::StringPieceHash>
       RecordMap;
 
   void AddProvider(ProgrammaticProvider* p);
   void RemoveProvider(ProgrammaticProvider* p);
 
   // Returns true if the two RecordMaps contain the same values (the origins
@@ skipping 38 matching lines @@
 
   typedef std::set<ProgrammaticProvider*> ProviderSet;
   ProviderSet programmatic_providers_;
 
   SourceDir source_dir_;
 
   DISALLOW_COPY_AND_ASSIGN(Scope);
 };
 
 #endif  // TOOLS_GN_SCOPE_H_