Add forward_variables_from() and target() to GN

tools/gn/functions.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_FUNCTIONS_H_
 #define TOOLS_GN_FUNCTIONS_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 120 matching lines @@
                     Err* err);
 
 extern const char kForEach[];
 extern const char kForEach_HelpShort[];
 extern const char kForEach_Help[];
 Value RunForEach(Scope* scope,
                  const FunctionCallNode* function,
                  const ListNode* args_list,
                  Err* err);
 
+extern const char kForwardVariablesFrom[];
+extern const char kForwardVariablesFrom_HelpShort[];
+extern const char kForwardVariablesFrom_Help[];
+Value RunForwardVariablesFrom(Scope* scope,
+                              const FunctionCallNode* function,
+                              const ListNode* args_list,
+                              Err* err);
+
 extern const char kGetEnv[];
 extern const char kGetEnv_HelpShort[];
 extern const char kGetEnv_Help[];
 Value RunGetEnv(Scope* scope,
                 const FunctionCallNode* function,
                 const std::vector<Value>& args,
                 Err* err);
 
 extern const char kGetLabelInfo[];
 extern const char kGetLabelInfo_HelpShort[];
@@ skipping 113 matching lines @@
 
 extern const char kStaticLibrary[];
 extern const char kStaticLibrary_HelpShort[];
 extern const char kStaticLibrary_Help[];
 Value RunStaticLibrary(Scope* scope,
                        const FunctionCallNode* function,
                        const std::vector<Value>& args,
                        BlockNode* block,
                        Err* err);
 
+extern const char kTarget[];
+extern const char kTarget_HelpShort[];
+extern const char kTarget_Help[];
+Value RunTarget(Scope* scope,
+                const FunctionCallNode* function,
+                const std::vector<Value>& args,
+                BlockNode* block,
+                Err* err);
+
 extern const char kTemplate[];
 extern const char kTemplate_HelpShort[];
 extern const char kTemplate_Help[];
 Value RunTemplate(Scope* scope,
                   const FunctionCallNode* function,
                   const std::vector<Value>& args,
                   BlockNode* block,
                   Err* err);
 
 extern const char kTool[];
@@ skipping 123 matching lines @@
 // Returns the name of the toolchain for the given scope.
 const Label& ToolchainLabelForScope(const Scope* scope);
 
 // Generates a label for the given scope, using the current directory and
 // toolchain, and the given name.
 Label MakeLabelForScope(const Scope* scope,
                         const FunctionCallNode* function,
                         const std::string& name);
 
 #endif  // TOOLS_GN_FUNCTIONS_H_