Normalize away "./" when writing Ninja short rules.

tools/gn/ninja_build_writer.cc

 // 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.
 
 #include "tools/gn/ninja_build_writer.h"
 
 #include <fstream>
 #include <map>
 
 #include "base/command_line.h"
@@ skipping 173 matching lines @@
     if (dir_string.size() == label.name().size() + 3 &&  // Size matches.
         dir_string[0] == '/' && dir_string[1] == '/' &&  // "//" at beginning.
         dir_string[dir_string.size() - 1] == '/' &&  // "/" at end.
         dir_string.compare(2, label.name().size(), label.name()) == 0)
       toplevel_targets.push_back(target);
   }
 
   for (size_t i = 0; i < default_toolchain_targets_.size(); i++) {
     const Target* target = default_toolchain_targets_[i];
     const Label& label = target->label();
-    const OutputFile& target_file = target->dependency_output_file();
+    OutputFile target_file(target->dependency_output_file());
+    // The output files may have leading "./" so normalize those away.
+    NormalizePath(&target_file.value());
 
     // Write the long name "foo/bar:baz" for the target "//foo/bar:baz".
     std::string long_name = label.GetUserVisibleName(false);
     base::TrimString(long_name, "/", &long_name);
     WritePhonyRule(target, target_file, long_name);
 
     // Write the directory name with no target name if they match
     // (e.g. "//foo/bar:bar" -> "foo/bar").
     if (FindLastDirComponent(label.dir()) == label.name()) {
       std::string medium_name =  DirectoryWithNoLastSlash(label.dir());
@@ skipping 38 matching lines @@
   EscapeOptions ninja_escape;
   ninja_escape.mode = ESCAPE_NINJA;
 
   // Escape for special chars Ninja will handle.
   std::string escaped = EscapeString(phony_name, ninja_escape, NULL);
 
   out_ << "build " << escaped << ": phony ";
   path_output_.WriteFile(out_, target_file);
   out_ << std::endl;
 }