Make Thread's task queue TimeDomain configurable

Adds a field to Thread::Options to allow the task queue time domain to
be configured, to enable Thread users to test task posting functionality
using synthetic time.

Bug: 1034758
Change-Id: I9b301f98e856a86045a12bab6e25569d4ef9b330
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2020480Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735444}

base/threading/thread.cc

@@ -50,14 +50,16 @@ class SequenceManagerThreadDelegate : public Thread::Delegate {
  public:
   explicit SequenceManagerThreadDelegate(
       MessagePumpType message_pump_type,
-      OnceCallback<std::unique_ptr<MessagePump>()> message_pump_factory)
+      OnceCallback<std::unique_ptr<MessagePump>()> message_pump_factory,
+      sequence_manager::TimeDomain* time_domain)
       : sequence_manager_(
             sequence_manager::internal::SequenceManagerImpl::CreateUnbound(
                 sequence_manager::SequenceManager::Settings::Builder()
                     .SetMessagePumpType(message_pump_type)
                     .Build())),
         default_task_queue_(sequence_manager_->CreateTaskQueue(
-            sequence_manager::TaskQueue::Spec("default_tq"))),
+            sequence_manager::TaskQueue::Spec("default_tq")
+                .SetTimeDomain(time_domain))),
         message_pump_factory_(std::move(message_pump_factory)) {
     sequence_manager_->SetDefaultTaskRunner(default_task_queue_->task_runner());
   }
@@ -158,15 +160,18 @@ bool Thread::StartWithOptions(const Options& options) {
 
   if (options.delegate) {
     DCHECK(!options.message_pump_factory);
+    DCHECK(!options.task_queue_time_domain_);
     delegate_ = WrapUnique(options.delegate);
   } else if (options.message_pump_factory) {
     delegate_ = std::make_unique<SequenceManagerThreadDelegate>(
-        MessagePumpType::CUSTOM, options.message_pump_factory);
+        MessagePumpType::CUSTOM, options.message_pump_factory,
+        options.task_queue_time_domain_);
   } else {
     delegate_ = std::make_unique<SequenceManagerThreadDelegate>(
         options.message_pump_type,
         BindOnce([](MessagePumpType type) { return MessagePump::Create(type); },
-                 options.message_pump_type));
+                 options.message_pump_type),
+        options.task_queue_time_domain_);
   }
 
   start_event_.Reset();

base/threading/thread.h

@@ -27,6 +27,9 @@ namespace base {
 
 class MessagePump;
 class RunLoop;
+namespace sequence_manager {
+class TimeDomain;
+}
 
 // IMPORTANT: Instead of creating a base::Thread, consider using
 // base::Create(Sequenced|SingleThread)TaskRunner().
@@ -91,6 +94,10 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
     // Specifies timer slack for thread message loop.
     TimerSlack timer_slack = TIMER_SLACK_NONE;
 
+    // The time domain to be used by the task queue. This is not compatible with
+    // a non-null |delegate|.
+    sequence_manager::TimeDomain* task_queue_time_domain_ = nullptr;
+
     // Used to create the MessagePump for the MessageLoop. The callback is Run()
     // on the thread. If message_pump_factory.is_null(), then a MessagePump
     // appropriate for |message_pump_type| is created. Setting this forces the