Remove duplication between TestRunner's fields and LayoutDumpFlags struct.

content/shell/renderer/layout_test/blink_test_runner.cc

Index: content/shell/renderer/layout_test/blink_test_runner.cc
diff --git a/content/shell/renderer/layout_test/blink_test_runner.cc b/content/shell/renderer/layout_test/blink_test_runner.cc
index 0a2bebaee559eb465a070021987fd8fc8c3f2052..3b13d52a07ef0fa2c2679028893362069fbaaf46 100644
--- a/content/shell/renderer/layout_test/blink_test_runner.cc
+++ b/content/shell/renderer/layout_test/blink_test_runner.cc
@@ -891,7 +891,7 @@ void BlinkTestRunner::CaptureDump() {
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDumpLineBoxTrees);
 
-  if (!layout_dump_flags.dump_child_frames) {
+  if (!layout_dump_flags.dump_child_frames()) {
     std::string layout_dump = DumpLayout(
         render_view()->GetMainRenderFrame()->GetWebFrame(), layout_dump_flags);
     OnLayoutDumpCompleted(layout_dump);