Add get_target_outputs function to GN

tools/gn/file_template_unittest.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 <sstream>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/escape.h"
 #include "tools/gn/file_template.h"
 
 TEST(FileTemplate, Static) {
   std::vector<std::string> templates;
   templates.push_back("something_static");
   FileTemplate t(templates);
   EXPECT_FALSE(t.has_substitutions());
 
   std::vector<std::string> result;
   t.ApplyString("", &result);
   ASSERT_EQ(1u, result.size());
   EXPECT_EQ("something_static", result[0]);
 
+  result.clear();
   t.ApplyString("lalala", &result);
   ASSERT_EQ(1u, result.size());
   EXPECT_EQ("something_static", result[0]);
 }
 
 TEST(FileTemplate, Typical) {
   std::vector<std::string> templates;
   templates.push_back("foo/{{source_name_part}}.cc");
   templates.push_back("foo/{{source_name_part}}.h");
   FileTemplate t(templates);
@@ skipping 48 matching lines @@
   EscapeOptions options;
   options.mode = ESCAPE_NINJA_SHELL;
   t.WriteNinjaVariablesForSubstitution(out, "../../foo/bar.txt", options);
 
   // Just the variables used above should be written.
   EXPECT_EQ(
       "  source = ../../foo/bar.txt\n"
       "  source_name_part = bar\n",
       out.str());
 }