Cleanup Mutex and related classes.

src/log-utils.h

Index: src/log-utils.h
diff --git a/src/log-utils.h b/src/log-utils.h
index 861a8263b84d80ad74ac71db92cafc0277c1dcce..ec8415e4b6ed5e31990cdc220c685d655df0061e 100644
--- a/src/log-utils.h
+++ b/src/log-utils.h
@@ -107,7 +107,7 @@ class Log {
 
    private:
     Log* log_;
-    ScopedLock sl;
+    LockGuard<Mutex> lock_guard_;
     int pos_;
   };
 
@@ -142,7 +142,7 @@ class Log {
 
   // mutex_ is a Mutex used for enforcing exclusive
   // access to the formatting buffer and the log file or log memory buffer.
-  Mutex* mutex_;
+  Mutex mutex_;
 
   // Buffer used for formatting log messages. This is a singleton buffer and
   // mutex_ should be acquired before using it.