Convert some more |base::Lock|s to |mojo::system::Mutex|s.

mojo/edk/system/incoming_endpoint.cc

Index: mojo/edk/system/incoming_endpoint.cc
diff --git a/mojo/edk/system/incoming_endpoint.cc b/mojo/edk/system/incoming_endpoint.cc
index cd091b1d2e2fee09a49157593a6ff4ce1279cf2c..cb67e05e57eddd3678145e8c59d981df39fe87b2 100644
--- a/mojo/edk/system/incoming_endpoint.cc
+++ b/mojo/edk/system/incoming_endpoint.cc
@@ -17,13 +17,14 @@ namespace system {
 IncomingEndpoint::IncomingEndpoint() {
 }
 
-scoped_refptr<ChannelEndpoint> IncomingEndpoint::Init() {
+scoped_refptr<ChannelEndpoint> IncomingEndpoint::Init()
+    MOJO_NO_THREAD_SAFETY_ANALYSIS {
   endpoint_ = new ChannelEndpoint(this, 0);
   return endpoint_;
 }
 
 scoped_refptr<MessagePipe> IncomingEndpoint::ConvertToMessagePipe() {
-  base::AutoLock locker(lock_);
+  MutexLocker locker(&mutex_);
   scoped_refptr<MessagePipe> message_pipe(
       MessagePipe::CreateLocalProxyFromExisting(&message_queue_,
                                                 endpoint_.get()));
@@ -35,7 +36,7 @@ scoped_refptr<MessagePipe> IncomingEndpoint::ConvertToMessagePipe() {
 scoped_refptr<DataPipe> IncomingEndpoint::ConvertToDataPipeProducer(
     const MojoCreateDataPipeOptions& validated_options,
     size_t consumer_num_bytes) {
-  base::AutoLock locker(lock_);
+  MutexLocker locker(&mutex_);
   scoped_refptr<DataPipe> data_pipe(DataPipe::CreateRemoteConsumerFromExisting(
       validated_options, consumer_num_bytes, &message_queue_, endpoint_.get()));
   DCHECK(message_queue_.IsEmpty());
@@ -45,7 +46,7 @@ scoped_refptr<DataPipe> IncomingEndpoint::ConvertToDataPipeProducer(
 
 scoped_refptr<DataPipe> IncomingEndpoint::ConvertToDataPipeConsumer(
     const MojoCreateDataPipeOptions& validated_options) {
-  base::AutoLock locker(lock_);
+  MutexLocker locker(&mutex_);
   scoped_refptr<DataPipe> data_pipe(DataPipe::CreateRemoteProducerFromExisting(
       validated_options, &message_queue_, endpoint_.get()));
   DCHECK(message_queue_.IsEmpty());
@@ -54,7 +55,7 @@ scoped_refptr<DataPipe> IncomingEndpoint::ConvertToDataPipeConsumer(
 }
 
 void IncomingEndpoint::Close() {
-  base::AutoLock locker(lock_);
+  MutexLocker locker(&mutex_);
   if (endpoint_) {
     endpoint_->DetachFromClient();
     endpoint_ = nullptr;
@@ -63,7 +64,7 @@ void IncomingEndpoint::Close() {
 
 bool IncomingEndpoint::OnReadMessage(unsigned /*port*/,
                                      MessageInTransit* message) {
-  base::AutoLock locker(lock_);
+  MutexLocker locker(&mutex_);
   if (!endpoint_)
     return false;