Change DONT_START_THREADS to DONT_CREATE_THREADS in TestBrowserThreadBundle.

content/public/test/test_browser_thread_bundle.cc

 // Copyright 2013 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 "content/public/test/test_browser_thread_bundle.h"
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/test/scoped_task_scheduler.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/public/test/test_browser_thread.h"
 
 namespace content {
 
 TestBrowserThreadBundle::TestBrowserThreadBundle()
     : TestBrowserThreadBundle(DEFAULT) {}
 
 TestBrowserThreadBundle::TestBrowserThreadBundle(int options)
-    : options_(options), threads_started_(false) {
+    : options_(options), threads_created_(false) {
   Init();
 }
 
 TestBrowserThreadBundle::~TestBrowserThreadBundle() {
+  DCHECK(threads_created_);
+
   // To avoid memory leaks, we must ensure that any tasks posted to the blocking
   // pool via PostTaskAndReply are able to reply back to the originating thread.
   // Thus we must flush the blocking pool while the browser threads still exist.
   base::RunLoop().RunUntilIdle();
   BrowserThreadImpl::FlushThreadPoolHelperForTesting();
 
   // To ensure a clean teardown, each thread's message loop must be flushed
   // just before the thread is destroyed. But stopping a fake thread does not
   // automatically flush the message loop, so we have to do it manually.
   // See http://crbug.com/247525 for discussion.
@@ skipping 23 matching lines @@
   // |message_loop_| needs to explicitly go away before fake threads in order
   // for DestructionObservers hooked to |message_loop_| to be able to invoke
   // BrowserThread::CurrentlyOn() -- ref. ~TestBrowserThread().
   CHECK(message_loop_->IsIdleForTesting());
   message_loop_.reset();
 }
 
 void TestBrowserThreadBundle::Init() {
   // Check for conflicting options can't have two IO threads.
   CHECK(!(options_ & IO_MAINLOOP) || !(options_ & REAL_IO_THREAD));
-  // There must be a thread to start to use DONT_START_THREADS
-  CHECK((options_ & ~IO_MAINLOOP) != DONT_START_THREADS);
+  // There must be a thread to start to use DONT_CREATE_THREADS
+  CHECK((options_ & ~IO_MAINLOOP) != DONT_CREATE_THREADS);
 
   if (options_ & IO_MAINLOOP) {
     message_loop_.reset(new base::MessageLoopForIO());
   } else {
     message_loop_.reset(new base::MessageLoopForUI());
   }
 
+  ui_thread_.reset(
+      new TestBrowserThread(BrowserThread::UI, message_loop_.get()));

[gab, 2017/01/12 19:47:35]

Why is the UI thread unconditionally created?

[fdoray, 2017/01/12 19:59:10]

TestBrowserThreadBundle::CreateThreads() mimics
BrowserMainLoop::CreateThreads(). BrowserMainLoop::CreateThreads() initializes
TaskScheduler and create non-UI BrowserThreads. The UI thread is created in
BrowserMainLoop::MainMessageLoopStart().

Note: The only user of DONT_CREATE_THREADS is IOThreadTestWithIOThreadObject.
This test needs the UI thread to exist (ThreadTaskRunnerHandle and
DCHECK_CURRENTLY_ON(BrowserThread::UI) work on the main thread) when the IO
thread hasn't been created yet.

[gab, 2017/01/12 20:13:27]

I see, then add a comment to that effect here and lgtm

[fdoray, 2017/01/12 21:02:56]

Done.

+
+  if (!(options_ & DONT_CREATE_THREADS))
+    CreateThreads();
+}
+
+void TestBrowserThreadBundle::CreateThreads() {
+  DCHECK(!threads_created_);
+
   task_scheduler_.reset(
       new base::test::ScopedTaskScheduler(message_loop_.get()));
 
-  ui_thread_.reset(
-      new TestBrowserThread(BrowserThread::UI, message_loop_.get()));
-
   if (options_ & REAL_DB_THREAD) {
     db_thread_.reset(new TestBrowserThread(BrowserThread::DB));
+    db_thread_->Start();
   } else {
     db_thread_.reset(
         new TestBrowserThread(BrowserThread::DB, message_loop_.get()));
   }
 
   if (options_ & REAL_FILE_THREAD) {
     file_thread_.reset(new TestBrowserThread(BrowserThread::FILE));
+    file_thread_->Start();
   } else {
     file_thread_.reset(
         new TestBrowserThread(BrowserThread::FILE, message_loop_.get()));
   }
 
   file_user_blocking_thread_.reset(new TestBrowserThread(
       BrowserThread::FILE_USER_BLOCKING, message_loop_.get()));
   process_launcher_thread_.reset(new TestBrowserThread(
       BrowserThread::PROCESS_LAUNCHER, message_loop_.get()));
   cache_thread_.reset(
       new TestBrowserThread(BrowserThread::CACHE, message_loop_.get()));
 
   if (options_ & REAL_IO_THREAD) {
     io_thread_.reset(new TestBrowserThread(BrowserThread::IO));
+    io_thread_->StartIOThread();
   } else {
     io_thread_.reset(
         new TestBrowserThread(BrowserThread::IO, message_loop_.get()));
   }
 
-  if (!(options_ & DONT_START_THREADS))
-    Start();
-}
-
-void TestBrowserThreadBundle::Start() {
-  DCHECK(!threads_started_);
-
-  if (options_ & REAL_DB_THREAD)
-    db_thread_->Start();
-
-  if (options_ & REAL_FILE_THREAD)
-    file_thread_->Start();
-
-  if (options_ & REAL_IO_THREAD)
-    io_thread_->StartIOThread();
-
-  threads_started_ = true;
+  threads_created_ = true;
 }
 
 }  // namespace content