[Blimp] Adds blimp engine browser test framework and LoadUrl test.

blimp/engine/app/test_content_main_delegate.cc

Index: blimp/engine/app/test_content_main_delegate.cc
diff --git a/blimp/engine/app/test_content_main_delegate.cc b/blimp/engine/app/test_content_main_delegate.cc
new file mode 100644
index 0000000000000000000000000000000000000000..77d05ab46f50eb073aea6ed6423c2b4d10d3c2cd
--- /dev/null
+++ b/blimp/engine/app/test_content_main_delegate.cc
@@ -0,0 +1,29 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/engine/app/test_content_main_delegate.h"
+
+namespace blimp {
+namespace engine {
+namespace {
+TestContentMainDelegate* g_content_main_delegate = nullptr;
+}  // namespace
+
+TestContentMainDelegate::TestContentMainDelegate() {
+  DCHECK(!g_content_main_delegate);
+  g_content_main_delegate = this;
+}
+
+TestContentMainDelegate::~TestContentMainDelegate() {
+  DCHECK_EQ(this, g_content_main_delegate);
+  g_content_main_delegate = nullptr;
+}
+
+// static
+TestContentMainDelegate* TestContentMainDelegate::GetInstance() {
+  return g_content_main_delegate;
+}
+
+}  // namespace engine
+}  // namespace blimp