Add GN function get_label_info

tools/gn/filesystem_utils.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_FILESYSTEM_UTILS_H_
 #define TOOLS_GN_FILESYSTEM_UTILS_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
@@ skipping 148 matching lines @@
 // given source_root, a source-relative directory will be returned (e.g.
 // "//foo/bar.cc". If it's outside of the source root, a system-absolute
 // directory will be returned.
 SourceDir SourceDirForPath(const base::FilePath& source_root,
                            const base::FilePath& path);
 
 // Like SourceDirForPath but returns the SourceDir representing the current
 // directory.
 SourceDir SourceDirForCurrentDirectory(const base::FilePath& source_root);
 
+// Given the label of a toolchain and whether that toolchain is the default
+// toolchain, returns the name of the subdirectory for that toolchain's
+// output. This will be the empty string to indicate that the toolchain outputs
+// go in the root build directory. Otherwise, the result will end in a slash.
+std::string GetOutputSubdirName(const Label& toolchain_label, bool is_default);
+
 // -----------------------------------------------------------------------------
 
 // These functions return the various flavors of output and gen directories.
 SourceDir GetToolchainOutputDir(const Settings* settings);
+SourceDir GetToolchainOutputDir(const BuildSettings* build_settings,
+                                const Label& label, bool is_default);
 SourceDir GetToolchainGenDir(const Settings* settings);
+SourceDir GetToolchainGenDir(const BuildSettings* build_settings,
+                             const Label& toolchain_label, bool is_default);
 SourceDir GetOutputDirForSourceDir(const Settings* settings,
                                    const SourceDir& source_dir);
 SourceDir GetGenDirForSourceDir(const Settings* settings,
                                 const SourceDir& source_dir);
 SourceDir GetTargetOutputDir(const Target* target);
 SourceDir GetTargetGenDir(const Target* target);
 SourceDir GetCurrentOutputDir(const Scope* scope);
 SourceDir GetCurrentGenDir(const Scope* scope);
 
 #endif  // TOOLS_GN_FILESYSTEM_UTILS_H_