Remove static Mutex construction.

runtime/vm/thread_registry.h

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_THREAD_REGISTRY_H_
 #define VM_THREAD_REGISTRY_H_
 
 #include "vm/globals.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/thread.h"
 
 namespace dart {
 
 // Unordered collection of threads relating to a particular isolate.
 class ThreadRegistry {
  public:
-  ThreadRegistry() : mutex_(), entries_() {}
+  ThreadRegistry() : mutex_(new Mutex()), entries_() {}
 
   bool RestoreStateTo(Thread* thread, Thread::State* state) {
-    MutexLocker ml(&mutex_);
+    MutexLocker ml(mutex_);
     Entry* entry = FindEntry(thread);
     if (entry != NULL) {
       Thread::State st = entry->state;
       // TODO(koda): Support same thread re-entering same isolate with
       // Dart frames in between. For now, just assert it doesn't happen.
       if (st.top_exit_frame_info != thread->top_exit_frame_info()) {
         ASSERT(thread->top_exit_frame_info() == 0 ||
                thread->top_exit_frame_info() > st.top_exit_frame_info);
       }
       ASSERT(!entry->scheduled);
@@ skipping 10 matching lines @@
     new_entry.scheduled = true;
 #if defined(DEBUG)
     // State field is not in use, so zap it.
     memset(&new_entry.state, 0xda, sizeof(new_entry.state));
 #endif
     entries_.Add(new_entry);
     return false;
   }
 
   void SaveStateFrom(Thread* thread, const Thread::State& state) {
-    MutexLocker ml(&mutex_);
+    MutexLocker ml(mutex_);
     Entry* entry = FindEntry(thread);
     ASSERT(entry != NULL);
     ASSERT(entry->scheduled);
     entry->scheduled = false;
     entry->state = state;
   }
 
   bool Contains(Thread* thread) {
-    MutexLocker ml(&mutex_);
+    MutexLocker ml(mutex_);
     return (FindEntry(thread) != NULL);
   }
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor) {
-    MutexLocker ml(&mutex_);
+    MutexLocker ml(mutex_);
     for (int i = 0; i < entries_.length(); ++i) {
       const Entry& entry = entries_[i];
       Zone* zone = entry.scheduled ? entry.thread->zone() : entry.state.zone;
       if (zone != NULL) {
         zone->VisitObjectPointers(visitor);
       }
     }
   }
 
  private:
   struct Entry {
     Thread* thread;
     bool scheduled;
     Thread::State state;
   };
 
   // Returns Entry corresponding to thread in registry or NULL.
   // Note: Lock should be taken before this function is called.
   Entry* FindEntry(Thread* thread) {
-    DEBUG_ASSERT(mutex_.IsOwnedByCurrentThread());
+    DEBUG_ASSERT(mutex_->IsOwnedByCurrentThread());
     for (int i = 0; i < entries_.length(); ++i) {
       if (entries_[i].thread == thread) {
         return &entries_[i];
       }
     }
     return NULL;
   }
 
-  Mutex mutex_;
+  Mutex* mutex_;
   MallocGrowableArray<Entry> entries_;
 
 
   DISALLOW_COPY_AND_ASSIGN(ThreadRegistry);
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_REGISTRY_H_