Refactor GN source expansions.

tools/gn/target_generator.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_TARGET_GENERATOR_H_
 #define TOOLS_GN_TARGET_GENERATOR_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 36 matching lines @@
   virtual void DoRun() = 0;
 
   const BuildSettings* GetBuildSettings() const;
 
   void FillSources();
   void FillPublic();
   void FillInputs();
   void FillConfigs();
   void FillOutputs();
 
+  // Rrturns true if the given pattern will expand to a file in the output
+  // directory. If not, returns false and sets the error, blaming the given
+  // Value.
+  bool EnsureSubstitutionIsInOutputDir(
+      const SubstitutionPattern& pattern,
+      const Value& original_value);
+
   Target* target_;
   Scope* scope_;
   const FunctionCallNode* function_call_;
   Err* err_;
 
  private:
   void FillDependentConfigs();  // Includes all types of dependent configs.
   void FillData();
   void FillDependencies();  // Includes data dependencies.
 
   // Reads configs/deps from the given var name, and uses the given setting on
   // the target to save them.
   void FillGenericConfigs(const char* var_name, LabelConfigVector* dest);
   void FillGenericDeps(const char* var_name, LabelTargetVector* dest);
 
   void FillForwardDependentConfigs();
 
   DISALLOW_COPY_AND_ASSIGN(TargetGenerator);
 };
 
 #endif  // TOOLS_GN_TARGET_GENERATOR_H_