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

blimp/engine/testing/app/blimp_browser_testing_main_parts.cc

+// 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/testing/app/blimp_browser_testing_main_parts.h"
+
+#include <utility>
+
+#include "base/command_line.h"
+#include "base/memory/ptr_util.h"
+#include "base/threading/thread_restrictions.h"
+#include "blimp/common/proto/blimp_message.pb.h"
+#include "blimp/engine/app/blimp_engine_config.h"
+#include "blimp/engine/app/settings_manager.h"
+#include "blimp/engine/common/blimp_browser_context.h"
+#include "blimp/engine/feature/geolocation/blimp_location_provider.h"
+#include "blimp/engine/session/blimp_engine_session.h"
+#include "blimp/engine/testing/app/blimp_url_rewriter.h"
+#include "blimp/engine/testing/session/blimp_engine_testing_session.h"
+#include "blimp/net/blimp_connection.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/browser_url_handler.h"
+#include "content/public/common/main_function_params.h"
+#include "net/base/net_module.h"
+#include "net/log/net_log.h"
+#include "net/test/embedded_test_server/embedded_test_server.h"
+
+namespace blimp {
+namespace engine {
+
+const base::FilePath::CharType kBlimpTestRoot[] = FILE_PATH_LITERAL("");
+
+BlimpBrowserTestingMainParts::BlimpBrowserTestingMainParts(
+    const content::MainFunctionParams& parameters)
+    : BlimpBrowserMainParts(parameters){};
+
+void BlimpBrowserTestingMainParts::PreEarlyInitialization() {
+  // Fetch the engine config from the command line, and crash if invalid. Allow
+  // IO operations even though this is not in the FILE thread as this is
+  // necessary for Blimp startup and occurs before any user interaction.
+  {

[Kevin M, 2017/01/09 20:17:17]

Remove unnecessary curly braces?

[shenghuazhang, 2017/01/10 23:20:49]

Done.

+    const base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    engine_config_ = BlimpEngineConfig::Create(*cmd_line);
+    CHECK(engine_config_);
+  }
+}
+
+void BlimpBrowserTestingMainParts::PreMainMessageLoopRun() {
+  blimp::engine::test::g_ets_instance.reset(new net::EmbeddedTestServer());

[Kevin M, 2017/01/09 20:17:17]

Why is this a global singleton? Can we bind an instance here and pass pointers
to it into handlers etc.?

[shenghuazhang, 2017/01/10 23:20:49]

The embedded_test_server instance is called by the url rewriter handler method
(HandleBlimpTestURL() in
https://codereview.chromium.org/2572563006/diff/60001/blimp/engine/testing/ap...),
and it needs to be started once when the engine session starts.

And the HandleBlimpTestURL which is passed into the handler below should be the
same type of URLHandler
(https://codesearch.chromium.org/chromium/src/content/public/browser/browser_u...).
So the additional g_ets_instance may not be able to be passed into handler
directly.

[Kevin M, 2017/01/11 00:28:14]

Got it. I wonder why this a free function, and not an object, or a Callback?
Weird.

+  blimp::engine::test::g_ets_instance->ServeFilesFromSourceDirectory(
+      base::FilePath(kBlimpTestRoot));
+  DCHECK(blimp::engine::test::g_ets_instance->Start());
+
+  content::BrowserURLHandler::GetInstance()->AddHandlerPair(
+      &blimp::engine::test::HandleBlimpTestURL,
+      content::BrowserURLHandler::null_handler());
+
+  net_log_.reset(new net::NetLog());

[Kevin M, 2017/01/09 20:17:17]

nit: use base::MakeUnique<X>() instead of "new X"

[shenghuazhang, 2017/01/10 23:20:49]

Done.

+
+  std::unique_ptr<SettingsManager> settings_manager_;
+  settings_manager_.reset(new SettingsManager);
+  std::unique_ptr<BlimpBrowserContext> browser_context(
+      new BlimpBrowserContext(false, net_log_.get()));
+
+  std::unique_ptr<BlimpEngineSession> engine_session_;
+  engine_session_.reset(new BlimpEngineTestingSession(
+      std::move(browser_context), net_log_.get(), engine_config_.get(),
+      settings_manager_.get()));
+  engine_session_->Initialize();
+  BlimpBrowserMainParts::SetSettingsManagerForTesting(
+      std::move(settings_manager_));
+  BlimpBrowserMainParts::SetEngineSessionForTesting(std::move(engine_session_));
+}
+
+void BlimpBrowserTestingMainParts::PostMainMessageLoopRun() {
+  BlimpBrowserMainParts::PostMainMessageLoopRun();
+  DCHECK(blimp::engine::test::g_ets_instance->ShutdownAndWaitUntilComplete());
+}
+
+}  // namespace engine
+}  // namespace blimp