[Blimp] Refactor Blimp test engine with embedded test server and URL rewriting

blimp/engine/app/blimp_browser_main_parts.cc

Index: blimp/engine/app/blimp_browser_main_parts.cc
diff --git a/blimp/engine/app/blimp_browser_main_parts.cc b/blimp/engine/app/blimp_browser_main_parts.cc
index 32e405c65a1a240f452c0349c779a5dab668035a..d299a417f8549b3666209ff9c6afe26ea145b1fc 100644
--- a/blimp/engine/app/blimp_browser_main_parts.cc
+++ b/blimp/engine/app/blimp_browser_main_parts.cc
@@ -56,6 +56,16 @@ void BlimpBrowserMainParts::PostMainMessageLoopRun() {
   engine_session_.reset();
 }
 
+void BlimpBrowserMainParts::SetSettingsManagerForTesting(
+    std::unique_ptr<SettingsManager> settings_manager) {
+  settings_manager_ = std::move(settings_manager);
+}
+
+void BlimpBrowserMainParts::SetEngineSessionForTesting(
+    std::unique_ptr<BlimpEngineSession> engine_session) {
+  engine_session_ = std::move(engine_session);
+}
+
 BlimpBrowserContext* BlimpBrowserMainParts::GetBrowserContext() {
   return engine_session_->browser_context();
 }