Remove remaining legacy SplitString calls.

tools/gn/command_clean.cc

 // Copyright 2015 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/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/err.h"
 #include "tools/gn/setup.h"
 
 namespace {
 
 // Extracts from a build.ninja the commands to run GN.
 //
 // The commands to run GN are the gn rule and build.ninja build step at the top
 // of the build.ninja file. We want to keep these when deleting GN builds since
 // we want to preserve the command-line flags to GN.
 //
 // On error, returns the empty string.
 std::string ExtractGNBuildCommands(const base::FilePath& build_ninja_file) {
   std::string file_contents;
   if (!base::ReadFileToString(build_ninja_file, &file_contents)) {
     return std::string();
   }
 
-  std::vector<std::string> lines;
-  base::SplitStringDontTrim(file_contents, '\n', &lines);
+  std::vector<std::string> lines = base::SplitString(
+      file_contents, "\n", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
 
   std::string result;
   int num_blank_lines = 0;
   for (const auto& line : lines) {
     result += line;
     result += "\n";
     if (line.empty()) {
       ++num_blank_lines;
     }
     if (num_blank_lines == 2)
@@ skipping 101 matching lines @@
                       static_cast<int>(dummy_content.size())) == -1) {
     Err(Location(), std::string("Failed to write build.ninja.d."))
         .PrintToStdout();
     return 1;
   }
 
   return 0;
 }
 
 }  // namespace commands