Revert of Add joinable option to SimpleThread::Options as was just done for Thread.

base/threading/simple_thread.cc

Index: base/threading/simple_thread.cc
diff --git a/base/threading/simple_thread.cc b/base/threading/simple_thread.cc
index fa1a3449e057e2176244b092ab9b20b4ef88ba8e..6c64a17d6ab2fea1ec792715ad4697adcc21bd94 100644
--- a/base/threading/simple_thread.cc
+++ b/base/threading/simple_thread.cc
@@ -12,29 +12,39 @@
 namespace base {
 
 SimpleThread::SimpleThread(const std::string& name_prefix)
-    : SimpleThread(name_prefix, Options()) {}
+    : name_prefix_(name_prefix),
+      name_(name_prefix),
+      thread_(),
+      event_(WaitableEvent::ResetPolicy::MANUAL,
+             WaitableEvent::InitialState::NOT_SIGNALED),
+      tid_(0),
+      joined_(false) {}
 
 SimpleThread::SimpleThread(const std::string& name_prefix,
                            const Options& options)
     : name_prefix_(name_prefix),
       name_(name_prefix),
       options_(options),
+      thread_(),
       event_(WaitableEvent::ResetPolicy::MANUAL,
-             WaitableEvent::InitialState::NOT_SIGNALED) {}
+             WaitableEvent::InitialState::NOT_SIGNALED),
+      tid_(0),
+      joined_(false) {}
 
 SimpleThread::~SimpleThread() {
   DCHECK(HasBeenStarted()) << "SimpleThread was never started.";
-  DCHECK(thread_.is_null()) << "Joinable SimpleThread destroyed without being "
-                            << "Join()ed.";
+  DCHECK(HasBeenJoined()) << "SimpleThread destroyed without being Join()ed.";
 }
 
 void SimpleThread::Start() {
   DCHECK(!HasBeenStarted()) << "Tried to Start a thread multiple times.";
-  bool success = options_.joinable
-      ? PlatformThread::CreateWithPriority(options_.stack_size, this,
-                                           &thread_, options_.priority)
-      : PlatformThread::CreateNonJoinableWithPriority(
-            options_.stack_size, this, options_.priority);
+  bool success;
+  if (options_.priority() == ThreadPriority::NORMAL) {
+    success = PlatformThread::Create(options_.stack_size(), this, &thread_);
+  } else {
+    success = PlatformThread::CreateWithPriority(options_.stack_size(), this,
+                                                 &thread_, options_.priority());
+  }
   DCHECK(success);
   base::ThreadRestrictions::ScopedAllowWait allow_wait;
   event_.Wait();  // Wait for the thread to complete initialization.
@@ -43,9 +53,7 @@
 void SimpleThread::Join() {
   DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread.";
   DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times.";
-  DCHECK(!thread_.is_null()) << "A non-joinable thread can't be joined.";
   PlatformThread::Join(thread_);
-  thread_ = PlatformThreadHandle();
   joined_ = true;
 }