Simplify implementation of Mutex.

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index 8b27c19a65f45d92cb8fdf2f52f0adad14715865..51d5698273f9a089f440342e63132a11ae9964dd 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -100,7 +100,7 @@ int random();
 
 #endif  // WIN32
 
-#include "lazy-instance.h"
+#include "mutex.h"
 #include "utils.h"
 #include "v8globals.h"
 
@@ -309,10 +309,6 @@ class OS {
 
   static int StackWalk(Vector<StackFrame> frames);
 
-  // Factory method for creating platform dependent Mutex.
-  // Please use delete to reclaim the storage for the returned Mutex.
-  static Mutex* CreateMutex();
-
   // Factory method for creating platform dependent Semaphore.
   // Please use delete to reclaim the storage for the returned Semaphore.
   static Semaphore* CreateSemaphore(int count);
@@ -716,72 +712,6 @@ class Thread {
 
 
 // ----------------------------------------------------------------------------
-// Mutex
-//
-// Mutexes are used for serializing access to non-reentrant sections of code.
-// The implementations of mutex should allow for nested/recursive locking.
-
-class Mutex {
- public:
-  virtual ~Mutex() {}
-
-  // Locks the given mutex. If the mutex is currently unlocked, it becomes
-  // locked and owned by the calling thread, and immediately. If the mutex
-  // is already locked by another thread, suspends the calling thread until
-  // the mutex is unlocked.
-  virtual int Lock() = 0;
-
-  // Unlocks the given mutex. The mutex is assumed to be locked and owned by
-  // the calling thread on entrance.
-  virtual int Unlock() = 0;
-
-  // Tries to lock the given mutex. Returns whether the mutex was
-  // successfully locked.
-  virtual bool TryLock() = 0;
-};
-
-struct CreateMutexTrait {
-  static Mutex* Create() {
-    return OS::CreateMutex();
-  }
-};
-
-// POD Mutex initialized lazily (i.e. the first time Pointer() is called).
-// Usage:
-//   static LazyMutex my_mutex = LAZY_MUTEX_INITIALIZER;
-//
-//   void my_function() {
-//     ScopedLock my_lock(my_mutex.Pointer());
-//     // Do something.
-//   }
-//
-typedef LazyDynamicInstance<
-    Mutex, CreateMutexTrait, ThreadSafeInitOnceTrait>::type LazyMutex;
-
-#define LAZY_MUTEX_INITIALIZER LAZY_DYNAMIC_INSTANCE_INITIALIZER
-
-// ----------------------------------------------------------------------------
-// ScopedLock
-//
-// Stack-allocated ScopedLocks provide block-scoped locking and
-// unlocking of a mutex.
-class ScopedLock {
- public:
-  explicit ScopedLock(Mutex* mutex): mutex_(mutex) {
-    ASSERT(mutex_ != NULL);
-    mutex_->Lock();
-  }
-  ~ScopedLock() {
-    mutex_->Unlock();
-  }
-
- private:
-  Mutex* mutex_;
-  DISALLOW_COPY_AND_ASSIGN(ScopedLock);
-};
-
-
-// ----------------------------------------------------------------------------
 // Socket
 //