Add more phony rules to GN build

tools/gn/filesystem_utils_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 "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/filesystem_utils.h"
 
@@ skipping 55 matching lines @@
   std::string input;
   EXPECT_EQ("", FindDir(&input));
   input = "/";
   EXPECT_EQ("/", FindDir(&input));
   input = "foo/";
   EXPECT_EQ("foo/", FindDir(&input));
   input = "foo/bar/baz";
   EXPECT_EQ("foo/bar/", FindDir(&input));
 }
 
+TEST(FilesystemUtils, FindLastDirComponent) {
+  SourceDir empty;
+  EXPECT_EQ("", FindLastDirComponent(empty));
+
+  SourceDir root("/");
+  EXPECT_EQ("", FindLastDirComponent(root));
+
+  SourceDir srcroot("//");
+  EXPECT_EQ("", FindLastDirComponent(srcroot));
+
+  SourceDir regular1("//foo/");
+  EXPECT_EQ("foo", FindLastDirComponent(regular1));
+
+  SourceDir regular2("//foo/bar/");
+  EXPECT_EQ("bar", FindLastDirComponent(regular2));
+}
+
 TEST(FilesystemUtils, IsPathAbsolute) {
   EXPECT_TRUE(IsPathAbsolute("/foo/bar"));
   EXPECT_TRUE(IsPathAbsolute("/"));
   EXPECT_FALSE(IsPathAbsolute(""));
   EXPECT_FALSE(IsPathAbsolute("//"));
   EXPECT_FALSE(IsPathAbsolute("//foo/bar"));
 
 #if defined(OS_WIN)
   EXPECT_TRUE(IsPathAbsolute("C:/foo"));
   EXPECT_TRUE(IsPathAbsolute("C:/"));
@@ skipping 289 matching lines @@
   build_settings.SetBuildDir(SourceDir("//"));
   Settings settings(&build_settings, "");
 
   EXPECT_EQ("//", GetToolchainOutputDir(&settings).value());
   EXPECT_EQ("//gen/", GetToolchainGenDir(&settings).value());
   EXPECT_EQ("//obj/",
             GetOutputDirForSourceDir(&settings, SourceDir("//")).value());
   EXPECT_EQ("//gen/",
             GetGenDirForSourceDir(&settings, SourceDir("//")).value());
 }