Deprecate grpc::thread and sync in favor of std::thread,mutex,etc
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index ca4515d..c073741 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -93,7 +93,7 @@
 
 void ClientContext::set_call(grpc_call* call,
                              const std::shared_ptr<Channel>& channel) {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   GPR_ASSERT(call_ == nullptr);
   call_ = call;
   channel_ = channel;
@@ -119,7 +119,7 @@
 }
 
 void ClientContext::TryCancel() {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   if (call_) {
     grpc_call_cancel(call_, nullptr);
   } else {
diff --git a/src/cpp/server/dynamic_thread_pool.cc b/src/cpp/server/dynamic_thread_pool.cc
index 4b226c2..95a819d 100644
--- a/src/cpp/server/dynamic_thread_pool.cc
+++ b/src/cpp/server/dynamic_thread_pool.cc
@@ -31,15 +31,15 @@
  *
  */
 
-#include <grpc++/impl/sync.h>
-#include <grpc++/impl/thd.h>
+#include <mutex>
+#include <thread>
 
 #include "src/cpp/server/dynamic_thread_pool.h"
 
 namespace grpc {
 DynamicThreadPool::DynamicThread::DynamicThread(DynamicThreadPool* pool)
     : pool_(pool),
-      thd_(new grpc::thread(&DynamicThreadPool::DynamicThread::ThreadFunc,
+      thd_(new std::thread(&DynamicThreadPool::DynamicThread::ThreadFunc,
                             this)) {}
 DynamicThreadPool::DynamicThread::~DynamicThread() {
   thd_->join();
@@ -49,7 +49,7 @@
 void DynamicThreadPool::DynamicThread::ThreadFunc() {
   pool_->ThreadFunc();
   // Now that we have killed ourselves, we should reduce the thread count
-  grpc::unique_lock<grpc::mutex> lock(pool_->mu_);
+  std::unique_lock<std::mutex> lock(pool_->mu_);
   pool_->nthreads_--;
   // Move ourselves to dead list
   pool_->dead_threads_.push_back(this);
@@ -62,7 +62,7 @@
 void DynamicThreadPool::ThreadFunc() {
   for (;;) {
     // Wait until work is available or we are shutting down.
-    grpc::unique_lock<grpc::mutex> lock(mu_);
+    std::unique_lock<std::mutex> lock(mu_);
     if (!shutdown_ && callbacks_.empty()) {
       // If there are too many threads waiting, then quit this thread
       if (threads_waiting_ >= reserve_threads_) {
@@ -91,7 +91,7 @@
       nthreads_(0),
       threads_waiting_(0) {
   for (int i = 0; i < reserve_threads_; i++) {
-    grpc::lock_guard<grpc::mutex> lock(mu_);
+    std::lock_guard<std::mutex> lock(mu_);
     nthreads_++;
     new DynamicThread(this);
   }
@@ -104,7 +104,7 @@
 }
 
 DynamicThreadPool::~DynamicThreadPool() {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   shutdown_ = true;
   cv_.notify_all();
   while (nthreads_ != 0) {
@@ -114,7 +114,7 @@
 }
 
 void DynamicThreadPool::Add(const std::function<void()>& callback) {
-  grpc::lock_guard<grpc::mutex> lock(mu_);
+  std::lock_guard<std::mutex> lock(mu_);
   // Add works to the callbacks list
   callbacks_.push(callback);
   // Increase pool size or notify as needed
diff --git a/src/cpp/server/dynamic_thread_pool.h b/src/cpp/server/dynamic_thread_pool.h
index 61b1cc9..4f8c411 100644
--- a/src/cpp/server/dynamic_thread_pool.h
+++ b/src/cpp/server/dynamic_thread_pool.h
@@ -34,12 +34,13 @@
 #ifndef GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
 #define GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
 
+#include <condition_variable>
 #include <list>
 #include <memory>
+#include <mutex>
 #include <queue>
+#include <thread>
 
-#include <grpc++/impl/sync.h>
-#include <grpc++/impl/thd.h>
 #include <grpc++/support/config.h>
 
 #include "src/cpp/server/thread_pool_interface.h"
@@ -61,12 +62,12 @@
 
    private:
     DynamicThreadPool* pool_;
-    std::unique_ptr<grpc::thread> thd_;
+    std::unique_ptr<std::thread> thd_;
     void ThreadFunc();
   };
-  grpc::mutex mu_;
-  grpc::condition_variable cv_;
-  grpc::condition_variable shutdown_cv_;
+  std::mutex mu_;
+  std::condition_variable cv_;
+  std::condition_variable shutdown_cv_;
   bool shutdown_;
   std::queue<std::function<void()>> callbacks_;
   int reserve_threads_;
diff --git a/src/cpp/server/server_cc.cc b/src/cpp/server/server_cc.cc
index 7f32848..b7cfd6d 100644
--- a/src/cpp/server/server_cc.cc
+++ b/src/cpp/server/server_cc.cc
@@ -379,7 +379,7 @@
 
 Server::~Server() {
   {
-    grpc::unique_lock<grpc::mutex> lock(mu_);
+    std::unique_lock<std::mutex> lock(mu_);
     if (started_ && !shutdown_) {
       lock.unlock();
       Shutdown();
@@ -501,7 +501,7 @@
 }
 
 void Server::ShutdownInternal(gpr_timespec deadline) {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   if (started_ && !shutdown_) {
     shutdown_ = true;
 
@@ -549,7 +549,7 @@
 }
 
 void Server::Wait() {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   while (started_ && !shutdown_notified_) {
     shutdown_cv_.wait(lock);
   }
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index 559b5bf8..a66ec4a 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -33,9 +33,10 @@
 
 #include <grpc++/server_context.h>
 
+#include <mutex>
+
 #include <grpc++/completion_queue.h>
 #include <grpc++/impl/call.h>
-#include <grpc++/impl/sync.h>
 #include <grpc++/support/time.h>
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
@@ -76,20 +77,20 @@
 
  private:
   bool CheckCancelledNoPluck() {
-    grpc::lock_guard<grpc::mutex> g(mu_);
+    std::lock_guard<std::mutex> g(mu_);
     return finalized_ ? (cancelled_ != 0) : false;
   }
 
   bool has_tag_;
   void* tag_;
-  grpc::mutex mu_;
+  std::mutex mu_;
   int refs_;
   bool finalized_;
   int cancelled_;
 };
 
 void ServerContext::CompletionOp::Unref() {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   if (--refs_ == 0) {
     lock.unlock();
     delete this;
@@ -105,7 +106,7 @@
 }
 
 bool ServerContext::CompletionOp::FinalizeResult(void** tag, bool* status) {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   finalized_ = true;
   bool ret = false;
   if (has_tag_) {
diff --git a/src/cpp/thread_manager/thread_manager.cc b/src/cpp/thread_manager/thread_manager.cc
index caae4c4..1450d00 100644
--- a/src/cpp/thread_manager/thread_manager.cc
+++ b/src/cpp/thread_manager/thread_manager.cc
@@ -31,13 +31,14 @@
  *
  */
 
-#include <grpc++/impl/sync.h>
-#include <grpc++/impl/thd.h>
-#include <grpc/support/log.h>
-#include <climits>
-
 #include "src/cpp/thread_manager/thread_manager.h"
 
+#include <climits>
+#include <mutex>
+#include <thread>
+
+#include <grpc/support/log.h>
+
 namespace grpc {
 
 ThreadManager::WorkerThread::WorkerThread(ThreadManager* thd_mgr)
@@ -59,7 +60,7 @@
 
 ThreadManager::~ThreadManager() {
   {
-    std::unique_lock<grpc::mutex> lock(mu_);
+    std::unique_lock<std::mutex> lock(mu_);
     GPR_ASSERT(num_threads_ == 0);
   }
 
@@ -67,29 +68,29 @@
 }
 
 void ThreadManager::Wait() {
-  std::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   while (num_threads_ != 0) {
     shutdown_cv_.wait(lock);
   }
 }
 
 void ThreadManager::Shutdown() {
-  std::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   shutdown_ = true;
 }
 
 bool ThreadManager::IsShutdown() {
-  std::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   return shutdown_;
 }
 
 void ThreadManager::MarkAsCompleted(WorkerThread* thd) {
   {
-    std::unique_lock<grpc::mutex> list_lock(list_mu_);
+    std::unique_lock<std::mutex> list_lock(list_mu_);
     completed_threads_.push_back(thd);
   }
 
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   num_threads_--;
   if (num_threads_ == 0) {
     shutdown_cv_.notify_one();
@@ -97,7 +98,7 @@
 }
 
 void ThreadManager::CleanupCompletedThreads() {
-  std::unique_lock<grpc::mutex> lock(list_mu_);
+  std::unique_lock<std::mutex> lock(list_mu_);
   for (auto thd = completed_threads_.begin(); thd != completed_threads_.end();
        thd = completed_threads_.erase(thd)) {
     delete *thd;
@@ -114,7 +115,7 @@
 // less than max threshold (i.e max_pollers_) and the total number of threads is
 // below the maximum threshold, we can let the current thread continue as poller
 bool ThreadManager::MaybeContinueAsPoller() {
-  std::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   if (shutdown_ || num_pollers_ > max_pollers_) {
     return false;
   }
@@ -127,7 +128,7 @@
 // threads currently blocked in PollForWork()) is below the threshold (i.e
 // min_pollers_) and the total number of threads is below the maximum threshold
 void ThreadManager::MaybeCreatePoller() {
-  grpc::unique_lock<grpc::mutex> lock(mu_);
+  std::unique_lock<std::mutex> lock(mu_);
   if (!shutdown_ && num_pollers_ < min_pollers_) {
     num_pollers_++;
     num_threads_++;
@@ -156,7 +157,7 @@
     WorkStatus work_status = PollForWork(&tag, &ok);
 
     {
-      grpc::unique_lock<grpc::mutex> lock(mu_);
+      std::unique_lock<std::mutex> lock(mu_);
       num_pollers_--;
 
       if (work_status == TIMEOUT && num_pollers_ > min_pollers_) {
diff --git a/src/cpp/thread_manager/thread_manager.h b/src/cpp/thread_manager/thread_manager.h
index 9cfdb8a..9c0569c 100644
--- a/src/cpp/thread_manager/thread_manager.h
+++ b/src/cpp/thread_manager/thread_manager.h
@@ -34,11 +34,12 @@
 #ifndef GRPC_INTERNAL_CPP_THREAD_MANAGER_H
 #define GRPC_INTERNAL_CPP_THREAD_MANAGER_H
 
+#include <condition_variable>
 #include <list>
 #include <memory>
+#include <mutex>
+#include <thread>
 
-#include <grpc++/impl/sync.h>
-#include <grpc++/impl/thd.h>
 #include <grpc++/support/config.h>
 
 namespace grpc {
@@ -115,7 +116,7 @@
     void Run();
 
     ThreadManager* thd_mgr_;
-    grpc::thread thd_;
+    std::thread thd_;
   };
 
   // The main funtion in ThreadManager
@@ -134,10 +135,10 @@
 
   // Protects shutdown_, num_pollers_ and num_threads_
   // TODO: sreek - Change num_pollers and num_threads_ to atomics
-  grpc::mutex mu_;
+  std::mutex mu_;
 
   bool shutdown_;
-  grpc::condition_variable shutdown_cv_;
+  std::condition_variable shutdown_cv_;
 
   // Number of threads doing polling
   int num_pollers_;
@@ -150,7 +151,7 @@
   // currently polling i.e num_pollers_)
   int num_threads_;
 
-  grpc::mutex list_mu_;
+  std::mutex list_mu_;
   std::list<WorkerThread*> completed_threads_;
 };