diff --git a/tools/gn/command_refs.cc b/tools/gn/command_refs.cc
index 57ea824..9c89114 100644
--- a/tools/gn/command_refs.cc
+++ b/tools/gn/command_refs.cc
@@ -138,7 +138,7 @@
       return true;
   }
   for (const auto& cur_file : target->data()) {
-    if (cur_file == file)
+    if (cur_file == file.value())
       return true;
   }
   return false;
diff --git a/tools/gn/output_file.cc b/tools/gn/output_file.cc
index 1b6db62..12845fb 100644
--- a/tools/gn/output_file.cc
+++ b/tools/gn/output_file.cc
@@ -10,8 +10,12 @@
 OutputFile::OutputFile() : value_() {
 }
 
-OutputFile::OutputFile(const base::StringPiece& str)
-    : value_(str.data(), str.size()) {
+OutputFile::OutputFile(std::string&& v)
+    : value_(v) {
+}
+
+OutputFile::OutputFile(const std::string& v)
+    : value_(v) {
 }
 
 OutputFile::OutputFile(const BuildSettings* build_settings,
diff --git a/tools/gn/output_file.h b/tools/gn/output_file.h
index 3e0e99d..5f43a64 100644
--- a/tools/gn/output_file.h
+++ b/tools/gn/output_file.h
@@ -17,7 +17,8 @@
 class OutputFile {
  public:
   OutputFile();
-  explicit OutputFile(const base::StringPiece& str);
+  explicit OutputFile(std::string&& v);
+  explicit OutputFile(const std::string& v);
   OutputFile(const BuildSettings* build_settings,
              const SourceFile& source_file);
   ~OutputFile();
diff --git a/tools/gn/runtime_deps.cc b/tools/gn/runtime_deps.cc
index a8dfb0b..097044f 100644
--- a/tools/gn/runtime_deps.cc
+++ b/tools/gn/runtime_deps.cc
@@ -36,13 +36,16 @@
   deps->push_back(std::make_pair(output_file, source));
 }
 
-// Automatically converts a SourceFile to an OutputFile.
-void AddIfNew(const SourceFile& source_file,
+// Automatically converts a string that looks like a source to an OutputFile.
+void AddIfNew(const std::string& str,
               const Target* source,
               RuntimeDepsVector* deps,
               std::set<OutputFile>* found_file) {
-  AddIfNew(OutputFile(source->settings()->build_settings(), source_file),
-           source, deps, found_file);
+  OutputFile output_file(RebasePath(
+      str,
+      source->settings()->build_settings()->build_dir(),
+      source->settings()->build_settings()->root_path_utf8()));
+  AddIfNew(output_file, source, deps, found_file);
 }
 
 // Returns the output file that the runtime deps considers for the given
@@ -82,7 +85,7 @@
     std::vector<SourceFile> outputs;
     target->action_values().GetOutputsAsSourceFiles(target, &outputs);
     for (const auto& output_file : outputs)
-      AddIfNew(output_file, target, deps, found_files);
+      AddIfNew(output_file.value(), target, deps, found_files);
   }
 
   // Non-data dependencies (both public and private).
@@ -132,9 +135,9 @@
     "  (see \"gn help --runtime-deps-list-file\").\n"
     "\n"
     "  To a first approximation, the runtime dependencies of a target are\n"
-    "  the set of \"data\" files and the shared libraries from all transitive\n"
-    "  dependencies. Executables and shared libraries are considered runtime\n"
-    "  dependencies of themselves.\n"
+    "  the set of \"data\" files, data directories, and the shared libraries\n"
+    "  from all transitive dependencies. Executables and shared libraries are\n"
+    "  considered runtime dependencies of themselves.\n"
     "\n"
     "Details\n"
     "\n"
diff --git a/tools/gn/runtime_deps_unittest.cc b/tools/gn/runtime_deps_unittest.cc
index 4b73abc..0210b37 100644
--- a/tools/gn/runtime_deps_unittest.cc
+++ b/tools/gn/runtime_deps_unittest.cc
@@ -49,17 +49,17 @@
 
   Target stat(setup.settings(), Label(SourceDir("//"), "stat"));
   InitTargetWithType(setup, &stat, Target::STATIC_LIBRARY);
-  stat.data().push_back(SourceFile("//stat.dat"));
+  stat.data().push_back("//stat.dat");
   ASSERT_TRUE(stat.OnResolved(&err));
 
   Target shared(setup.settings(), Label(SourceDir("//"), "shared"));
   InitTargetWithType(setup, &shared, Target::SHARED_LIBRARY);
-  shared.data().push_back(SourceFile("//shared.dat"));
+  shared.data().push_back("//shared.dat");
   ASSERT_TRUE(shared.OnResolved(&err));
 
   Target set(setup.settings(), Label(SourceDir("//"), "set"));
   InitTargetWithType(setup, &set, Target::SOURCE_SET);
-  set.data().push_back(SourceFile("//set.dat"));
+  set.data().push_back("//set.dat");
   ASSERT_TRUE(set.OnResolved(&err));
 
   Target main(setup.settings(), Label(SourceDir("//"), "main"));
@@ -67,7 +67,7 @@
   main.private_deps().push_back(LabelTargetPair(&stat));
   main.private_deps().push_back(LabelTargetPair(&shared));
   main.private_deps().push_back(LabelTargetPair(&set));
-  main.data().push_back(SourceFile("//main.dat"));
+  main.data().push_back("//main.dat");
   ASSERT_TRUE(main.OnResolved(&err));
 
   std::vector<std::pair<OutputFile, const Target*>> result =
@@ -112,7 +112,7 @@
 
   Target final_in(setup.settings(), Label(SourceDir("//"), "final_in"));
   InitTargetWithType(setup, &final_in, Target::SOURCE_SET);
-  final_in.data().push_back(SourceFile("//final_in.dat"));
+  final_in.data().push_back("//final_in.dat");
   ASSERT_TRUE(final_in.OnResolved(&err));
 
   Target datadep(setup.settings(), Label(SourceDir("//"), "datadep"));
@@ -122,7 +122,7 @@
 
   Target final_out(setup.settings(), Label(SourceDir("//"), "final_out"));
   InitTargetWithType(setup, &final_out, Target::SOURCE_SET);
-  final_out.data().push_back(SourceFile("//final_out.dat"));
+  final_out.data().push_back("//final_out.dat");
   ASSERT_TRUE(final_out.OnResolved(&err));
 
   Target dep(setup.settings(), Label(SourceDir("//"), "dep"));
@@ -168,7 +168,7 @@
 
   Target datadep(setup.settings(), Label(SourceDir("//"), "datadep"));
   InitTargetWithType(setup, &datadep, Target::ACTION);
-  datadep.data().push_back(SourceFile("//datadep.data"));
+  datadep.data().push_back("//datadep.data");
   datadep.action_values().outputs() =
       SubstitutionList::MakeForTest("//datadep.output");
   ASSERT_TRUE(datadep.OnResolved(&err));
@@ -176,14 +176,14 @@
   Target datadep_copy(setup.settings(), Label(SourceDir("//"), "datadep_copy"));
   InitTargetWithType(setup, &datadep_copy, Target::COPY_FILES);
   datadep_copy.sources().push_back(SourceFile("//input"));
-  datadep_copy.data().push_back(SourceFile("//datadep_copy.data"));
+  datadep_copy.data().push_back("//datadep_copy.data");
   datadep_copy.action_values().outputs() =
       SubstitutionList::MakeForTest("//datadep_copy.output");
   ASSERT_TRUE(datadep_copy.OnResolved(&err));
 
   Target dep(setup.settings(), Label(SourceDir("//"), "dep"));
   InitTargetWithType(setup, &dep, Target::ACTION);
-  dep.data().push_back(SourceFile("//dep.data"));
+  dep.data().push_back("//dep.data");
   dep.action_values().outputs() =
       SubstitutionList::MakeForTest("//dep.output");
   ASSERT_TRUE(dep.OnResolved(&err));
@@ -191,7 +191,7 @@
   Target dep_copy(setup.settings(), Label(SourceDir("//"), "dep_copy"));
   InitTargetWithType(setup, &dep_copy, Target::COPY_FILES);
   dep_copy.sources().push_back(SourceFile("//input"));
-  dep_copy.data().push_back(SourceFile("//dep_copy.data"));
+  dep_copy.data().push_back("//dep_copy/data/");  // Tests a directory.
   dep_copy.action_values().outputs() =
       SubstitutionList::MakeForTest("//dep_copy.output");
   ASSERT_TRUE(dep_copy.OnResolved(&err));
@@ -231,7 +231,7 @@
                         MakePair("../../dep.data", &dep)) !=
               result.end()) << GetVectorDescription(result);
   EXPECT_TRUE(std::find(result.begin(), result.end(),
-                        MakePair("../../dep_copy.data", &dep_copy)) !=
+                        MakePair("../../dep_copy/data/", &dep_copy)) !=
               result.end()) << GetVectorDescription(result);
 
   // Explicitly asking for the runtime deps of an action target only includes
diff --git a/tools/gn/target.h b/tools/gn/target.h
index 081f81e..0050048 100644
--- a/tools/gn/target.h
+++ b/tools/gn/target.h
@@ -120,9 +120,11 @@
   const FileList& inputs() const { return inputs_; }
   FileList& inputs() { return inputs_; }
 
-  // Runtime dependencies.
-  const FileList& data() const { return data_; }
-  FileList& data() { return data_; }
+  // Runtime dependencies. These are "file-like things" that can either be
+  // directories or files. They do not need to exist, these are just passed as
+  // runtime dependencies to external test systems as necessary.
+  const std::vector<std::string>& data() const { return data_; }
+  std::vector<std::string>& data() { return data_; }
 
   // Returns true if targets depending on this one should have an order
   // dependency.
@@ -270,7 +272,7 @@
   bool complete_static_lib_;
   bool testonly_;
   FileList inputs_;
-  FileList data_;
+  std::vector<std::string> data_;
 
   LabelTargetVector private_deps_;
   LabelTargetVector public_deps_;
diff --git a/tools/gn/target_generator.cc b/tools/gn/target_generator.cc
index f59a21b..6018147 100644
--- a/tools/gn/target_generator.cc
+++ b/tools/gn/target_generator.cc
@@ -201,12 +201,40 @@
   const Value* value = scope_->GetValue(variables::kData, true);
   if (!value)
     return true;
-
-  Target::FileList dest_data;
-  if (!ExtractListOfRelativeFiles(scope_->settings()->build_settings(), *value,
-                                  scope_->GetSourceDir(), &dest_data, err_))
+  if (!value->VerifyTypeIs(Value::LIST, err_))
     return false;
-  target_->data().swap(dest_data);
+
+  const std::vector<Value>& input_list = value->list_value();
+  std::vector<std::string>& output_list = target_->data();
+  output_list.reserve(input_list.size());
+
+  const SourceDir& dir = scope_->GetSourceDir();
+  const std::string& root_path =
+      scope_->settings()->build_settings()->root_path_utf8();
+
+  for (size_t i = 0; i < input_list.size(); i++) {
+    const Value& input = input_list[i];
+    if (!input.VerifyTypeIs(Value::STRING, err_))
+      return false;
+    const std::string& input_str = input.string_value();
+
+    // Treat each input as either a file or a directory, depending on the
+    // last character.
+    if (!input_str.empty() && input_str[input_str.size() - 1] == '/') {
+      // Resolve as directory.
+      SourceDir resolved =
+          dir.ResolveRelativeDir(input, input_str, err_, root_path);
+      if (err_->has_error())
+        return false;
+      output_list.push_back(resolved.value());
+    } else {
+      // Resolve as file.
+      SourceFile resolved = dir.ResolveRelativeFile(input, err_, root_path);
+      if (err_->has_error())
+        return false;
+      output_list.push_back(resolved.value());
+    }
+  }
   return true;
 }
 
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index 1cbfc9c..51a68d5 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -509,11 +509,11 @@
 const char kData_Help[] =
     "data: Runtime data file dependencies.\n"
     "\n"
-    "  Lists files required to run the given target. These are typically\n"
-    "  data files. The paths are interpreted as being relative to the current\n"
-    "  build file. Since these are runtime dependencies, they do not affect\n"
-    "  which targets are built or when. To declare input files to a script,\n"
-    "  use \"inputs\".\n"
+    "  Lists files or directories required to run the given target. These are\n"
+    "  typically data files or directories of data files. The paths are\n"
+    "  interpreted as being relative to the current build file. Since these\n"
+    "  are runtime dependencies, they do not affect which targets are built\n"
+    "  or when. To declare input files to a script, use \"inputs\".\n"
     "\n"
     "  Appearing in the \"data\" section does not imply any special handling\n"
     "  such as copying them to the output directory. This is just used for\n"
@@ -526,6 +526,11 @@
     "  generated files both in the \"outputs\" list as well as the \"data\"\n"
     "  list.\n"
     "\n"
+    "  By convention, directories are be listed with a trailing slash:\n"
+    "    data = [ \"test/data/\" ]\n"
+    "  However, no verification is done on these so GN doesn't enforce this.\n"
+    "  The paths are just rebased and passed along when requested.\n"
+    "\n"
     "  See \"gn help runtime_deps\" for how these are used.\n";
 
 const char kDataDeps[] = "data_deps";