VM thread shutdown.

runtime/vm/os_thread_android.cc

Index: runtime/vm/os_thread_android.cc
diff --git a/runtime/vm/os_thread_android.cc b/runtime/vm/os_thread_android.cc
index 377fd94807cc443b79c7fdf0fd8cc2bdcfc7b1bd..1f8de35eddac8e76db5ba4e95b7e106a20e3c4a7 100644
--- a/runtime/vm/os_thread_android.cc
+++ b/runtime/vm/os_thread_android.cc
@@ -101,9 +101,6 @@ int OSThread::Start(ThreadStartFunction function, uword parameter) {
   int result = pthread_attr_init(&attr);
   RETURN_ON_PTHREAD_FAILURE(result);
 
-  result = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-  RETURN_ON_PTHREAD_FAILURE(result);
-
   result = pthread_attr_setstacksize(&attr, OSThread::GetMaxStackSize());
   RETURN_ON_PTHREAD_FAILURE(result);
 
@@ -123,6 +120,7 @@ int OSThread::Start(ThreadStartFunction function, uword parameter) {
 ThreadLocalKey OSThread::kUnsetThreadLocalKey =
     static_cast<pthread_key_t>(-1);
 ThreadId OSThread::kInvalidThreadId = static_cast<ThreadId>(0);
+ThreadJoinId OSThread::kInvalidThreadJoinId = static_cast<ThreadJoinId>(0);
 
 ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
   pthread_key_t key = kUnsetThreadLocalKey;
@@ -158,8 +156,13 @@ ThreadId OSThread::GetCurrentThreadId() {
 }
 
 
-bool OSThread::Join(ThreadId id) {
-  return false;
+ThreadJoinId OSThread::GetCurrentThreadJoinId() {
+  return pthread_self();
+}
+
+
+void OSThread::Join(ThreadJoinId id) {
+  ASSERT(pthread_join(id, NULL) == 0);
 }