Initialize test configuration to a default value.

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 b0628dc839c5fd5e52c8b686dfdab5c84fbb5ce4..0d5e8525843bf5135e25fe09f9ae428ae57082ba 100644
--- a/content/shell/renderer/layout_test/blink_test_runner.cc
+++ b/content/shell/renderer/layout_test/blink_test_runner.cc
@@ -252,9 +252,11 @@ WebURL RewriteAbsolutePathInCsswgTest(const std::string& utf8_url) {
 BlinkTestRunner::BlinkTestRunner(RenderView* render_view)
     : RenderViewObserver(render_view),
       RenderViewObserverTracker<BlinkTestRunner>(render_view),
+      test_config_(mojom::ShellTestConfiguration::New()),
       is_main_window_(false),
       focus_on_next_commit_(false),
       leak_detector_(new LeakDetector(this)) {
+  test_config_->enable_pixel_dumping = true;

[Sam McNally, 2017/05/10 07:55:44]

Why does this default to true?

[Jia, 2017/05/10 22:55:29]

Because the old struct ShellTestConfiguration default initializes this field to
true. Please see https://codereview.chromium.org/2594913002
shell_test_configuration.cc

[Sam McNally, 2017/05/10 23:37:13]

In that case, maybe it makes sense to set that as the default in the mojom. See
https://chromium.googlesource.com/chromium/src/+/master/mojo/public/tools/bin....

[Jia, 2017/05/11 00:42:02]

Done. Thanks for pointing out!

 }
 
 BlinkTestRunner::~BlinkTestRunner() {