Remove remaining legacy SplitString calls.

tools/gn/runtime_deps.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 "tools/gn/runtime_deps.h"
 
 #include <map>
 #include <set>
 #include <sstream>
 
@@ skipping 223 matching lines @@
   if (!base::ReadFileToString(UTF8ToFilePath(deps_target_list_file),
                               &list_contents)) {
     *err = Err(Location(),
         std::string("File for --") + switches::kRuntimeDepsListFile +
             " doesn't exist.",
         "The file given was \"" + deps_target_list_file + "\"");
     return false;
   }
   load_trace.Done();
 
-  std::vector<std::string> lines;
-  base::SplitString(list_contents, '\n', &lines);
-
   SourceDir root_dir("//");
   Label default_toolchain_label = builder.loader()->GetDefaultToolchain();
-  for (const auto& line : lines) {
+  for (const auto& line : base::SplitString(
+           list_contents, "\n", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
     if (line.empty())
       continue;
     Label label = Label::Resolve(root_dir, default_toolchain_label,
                                  Value(nullptr, line), err);
     if (err->has_error())
       return false;
 
     const Item* item = builder.GetItem(label);
     const Target* target = item ? item->AsTarget() : nullptr;
     if (!target) {
       *err = Err(Location(), "The label \"" + label.GetUserVisibleName(true) +
           "\" isn't a target.",
           "When reading the line:\n  " + line + "\n"
           "from the --" + switches::kRuntimeDepsListFile + "=" +
           deps_target_list_file);
       return false;
     }
 
     // Currently this writes all runtime deps files sequentially. We generally
     // expect few of these. We can run this on the worker pool if it looks
     // like it's talking a long time.
     WriteRuntimeDepsFile(target);
   }
   return true;
 }