Revert "Updated MallocHooks to collect stack traces when memory is allocated."

runtime/vm/os_thread.h

 // Copyright (c) 2012, 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 RUNTIME_VM_OS_THREAD_H_
 #define RUNTIME_VM_OS_THREAD_H_
 
 #include "platform/globals.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
@@ skipping 98 matching lines @@
   }
 
   static bool GetCurrentStackBounds(uword* lower, uword* upper);
 
   // Used to temporarily disable or enable thread interrupts.
   void DisableThreadInterrupts();
   void EnableThreadInterrupts();
   bool ThreadInterruptsEnabled();
 
   // The currently executing thread, or NULL if not yet initialized.
-  static OSThread* TryCurrent() {
+  static OSThread* Current() {
     BaseThread* thread = GetCurrentTLS();
     OSThread* os_thread = NULL;
     if (thread != NULL) {
       if (thread->is_os_thread()) {
         os_thread = reinterpret_cast<OSThread*>(thread);
       } else {
         Thread* vm_thread = reinterpret_cast<Thread*>(thread);
         os_thread = GetOSThreadFromThread(vm_thread);
       }
-    }
-    return os_thread;
-  }
-
-  // The currently executing thread. If there is no currently executing thread,
-  // a new OSThread is created and returned.
-  static OSThread* Current() {
-    OSThread* os_thread = TryCurrent();
-    if (os_thread == NULL) {
+    } else {
       os_thread = CreateAndSetUnknownThread();
     }
     return os_thread;
   }
   static void SetCurrent(OSThread* current);
 
   // TODO(5411455): Use flag to override default value and Validate the
   // stack size by querying OS.
   static uword GetSpecifiedStackSize() {
     ASSERT(OSThread::kStackSizeBuffer < OSThread::GetMaxStackSize());
@@ skipping 204 matching lines @@
   friend class SafepointMonitorLocker;
   friend void Dart_TestMonitor();
   DISALLOW_COPY_AND_ASSIGN(Monitor);
 };
 
 
 }  // namespace dart
 
 
 #endif  // RUNTIME_VM_OS_THREAD_H_