Add test runner support for overriding web_security_enabled preference.

content/shell/renderer/test_runner/test_runner.cc

Index: content/shell/renderer/test_runner/test_runner.cc
diff --git a/content/shell/renderer/test_runner/test_runner.cc b/content/shell/renderer/test_runner/test_runner.cc
index a30aff1ef86576b861c582396592a020f91238e8..f93571bcf93441e72044b0f241d1c9973802c4fb 100644
--- a/content/shell/renderer/test_runner/test_runner.cc
+++ b/content/shell/renderer/test_runner/test_runner.cc
@@ -2496,6 +2496,8 @@ void TestRunner::OverridePreference(const std::string key,
     prefs->should_respect_image_orientation = value->BooleanValue();
   } else if (key == "WebKitWebAudioEnabled") {
     DCHECK(value->BooleanValue());
+  } else if (key == "WebKitWebSecurityEnabled") {
+    prefs->web_security_enabled = value->BooleanValue();
   } else {
     std::string message("Invalid name for preference: ");
     message.append(key);