Clean up thread handling in Blimp browser tests.

blimp/engine/browser_tests/blimp_browser_test.h

 // 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.
 
 #ifndef BLIMP_ENGINE_BROWSER_TESTS_BLIMP_BROWSER_TEST_H_
 #define BLIMP_ENGINE_BROWSER_TESTS_BLIMP_BROWSER_TEST_H_
 
 #include <memory>
 
+#include "base/synchronization/waitable_event.h"
 #include "content/public/test/browser_test_base.h"
 
 namespace base {
 class RunLoop;
 }
 
 namespace content {
 class WebContents;
 }
 
 namespace blimp {
 namespace client {
 struct Assignment;
 }  // namespace client
 
 namespace engine {
 class BlimpEngineSession;
 }  // namespace engine
 
 // Base class for tests which require a full instance of the Blimp engine.
 class BlimpBrowserTest : public content::BrowserTestBase {
  public:
   // Notify that an asynchronous test is now complete and the test runner should
   // exit.
   void QuitRunLoop();
 
+  // Tells RunUntilCompletion() to break and discontinue processing UI & IO
+  // thread MessageLoops.
+  void SignalCompletion();
+
  protected:
   BlimpBrowserTest();
   ~BlimpBrowserTest() override;
 
-  // Run an asynchronous test in a nested run loop. The caller should call
-  // QuitRunLoop() to notify that the test should finish.
-  void RunUntilQuit();
+  // Processes tasks in the UI and IO thread until SignalCompletion() is
+  // called.
+  void RunUntilCompletion();
 
   engine::BlimpEngineSession* GetEngineSession();
 
   client::Assignment GetAssignment();
 
   // testing::Test implementation.
   void SetUp() override;
 
   // content::BrowserTestBase implementation.
   void RunTestOnMainThreadLoop() override;
+  void SetUpCommandLine(base::CommandLine* command_line) override;
   void SetUpOnMainThread() override;
   void TearDownOnMainThread() override;
-  void SetUpCommandLine(base::CommandLine* command_line) override;
 
  private:
-  void OnGetEnginePort(uint16_t port);
+  // Stores the port number, which was retrieved asynchronously from
+  // BlimpEngineSession.
+  void set_engine_port(uint16_t port) { engine_port_ = port; }

[Wez, 2016/08/19 19:15:50]

nit: This comment doesn't make clear why we need this, versus just setting the
port member directly.

[Kevin M, 2016/08/19 21:43:33]

Done.

 
   uint16_t engine_port_;
-  std::unique_ptr<base::RunLoop> run_loop_;
+
+  // Used to signal the completion of asynchronous processing to
+  // RunUntilCompletion().
+  base::WaitableEvent completion_event_;
 
   DISALLOW_COPY_AND_ASSIGN(BlimpBrowserTest);
 };
 
 }  // namespace blimp
 
 #endif  // BLIMP_ENGINE_BROWSER_TESTS_BLIMP_BROWSER_TEST_H_