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

runtime/vm/os_macos.cc

 // 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.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "vm/os.h"
 
 #include <errno.h>           // NOLINT
@@ skipping 248 matching lines @@
     req = rem;
   }
 }
 
 
 void OS::DebugBreak() {
   __builtin_trap();
 }
 
 
-uintptr_t DART_NOINLINE OS::GetProgramCounter() {
-  return reinterpret_cast<uintptr_t>(
-      __builtin_extract_return_addr(__builtin_return_address(0)));
-}
-
-
 char* OS::StrNDup(const char* s, intptr_t n) {
 // strndup has only been added to Mac OS X in 10.7. We are supplying
 // our own copy here if needed.
 #if !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) ||                 \
     __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ <= 1060
   intptr_t len = strlen(s);
   if ((n < 0) || (len < 0)) {
     return NULL;
   }
   if (n < len) {
@@ skipping 154 matching lines @@
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)