remove use of Mutex in favour of std::{,recursive_}mutex

This is a pretty straightforward first pass over removing a number of uses of
Mutex in favor of std::mutex or std::recursive_mutex. The problem is that there
are interfaces which take Mutex::Locker & to lock internal locks. This patch
cleans up most of the easy cases. The only non-trivial change is in
CommandObjectTarget.cpp where a Mutex::Locker was split into two.

llvm-svn: 269877
diff --git a/lldb/source/Core/StreamCallback.cpp b/lldb/source/Core/StreamCallback.cpp
index d144b16..9f0adee 100644
--- a/lldb/source/Core/StreamCallback.cpp
+++ b/lldb/source/Core/StreamCallback.cpp
@@ -18,13 +18,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
-
-StreamCallback::StreamCallback (lldb::LogOutputCallback callback, void *baton) :
-    Stream (0, 4, eByteOrderBig),
-    m_callback (callback),
-    m_baton (baton),
-    m_accumulated_data (),
-    m_collection_mutex ()
+StreamCallback::StreamCallback(lldb::LogOutputCallback callback, void *baton)
+    : Stream(0, 4, eByteOrderBig), m_callback(callback), m_baton(baton), m_accumulated_data(), m_collection_mutex()
 {
 }
 
@@ -35,7 +30,7 @@
 StreamString &
 StreamCallback::FindStreamForThread(lldb::tid_t cur_tid)
 {
-    Mutex::Locker locker(m_collection_mutex);
+    std::lock_guard<std::mutex> guard(m_collection_mutex);
     collection::iterator iter = m_accumulated_data.find (cur_tid);
     if (iter == m_accumulated_data.end())
     {