Fix broken build on Win32 due to r11010.

Review URL: https://chromiumcodereview.appspot.com/9666055

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11011 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-win32.cc

@@ -1961,7 +1961,7 @@ class SamplerThread : public Thread {
         interval_(interval) {}
 
   static void AddActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
+    ScopedLock lock(mutex_.Pointer());
     SamplerRegistry::AddActiveSampler(sampler);
     if (instance_ == NULL) {
       instance_ = new SamplerThread(sampler->interval());
@@ -1972,7 +1972,7 @@ class SamplerThread : public Thread {
   }
 
   static void RemoveActiveSampler(Sampler* sampler) {
-    ScopedLock lock(mutex_);
+    ScopedLock lock(mutex_.Pointer());
     SamplerRegistry::RemoveActiveSampler(sampler);
     if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
       RuntimeProfiler::StopRuntimeProfilerThreadBeforeShutdown(instance_);