Fix UaF of BlinkTestRunner caused by incorrect base::Unretained.

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 5d2f98a9482e51b64b047808fb36ffbecdf32655..20d87dd8fb5242e2ea5f0bc8b49d4c5b300b7b3c 100644
--- a/content/shell/renderer/layout_test/blink_test_runner.cc
+++ b/content/shell/renderer/layout_test/blink_test_runner.cc
@@ -903,10 +903,7 @@ void BlinkTestRunner::OnPixelsDumpCompleted(const SkBitmap& snapshot) {
 void BlinkTestRunner::CaptureDumpComplete() {
   render_view()->GetWebView()->mainFrame()->stopLoading();
 
-  base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::Bind(base::IgnoreResult(&BlinkTestRunner::Send),
-                            base::Unretained(this),
-                            new ShellViewHostMsg_TestFinished(routing_id())));
+  Send(new ShellViewHostMsg_TestFinished(routing_id()));
 }
 
 mojom::LayoutTestBluetoothFakeAdapterSetter&