Fix monitor wait to be safepoint aware.

runtime/vm/heap.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/heap.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
 #include "vm/isolate.h"
@@ skipping 206 matching lines @@
     : StackResource(Thread::Current()),
       old_space_(isolate()->heap()->old_space()) {
   // It's not yet safe to iterate over a paged space while it's concurrently
   // sweeping, so wait for any such task to complete first.
   MonitorLocker ml(old_space_->tasks_lock());
 #if defined(DEBUG)
   // We currently don't support nesting of HeapIterationScopes.
   ASSERT(old_space_->iterating_thread_ != thread());
 #endif
   while (old_space_->tasks() > 0) {
-    ml.Wait();
+    ml.WaitWithSafepointCheck(thread());
   }
 #if defined(DEBUG)
   ASSERT(old_space_->iterating_thread_ == NULL);
   old_space_->iterating_thread_ = thread();
 #endif
   old_space_->set_tasks(1);
 }
 
 
 HeapIterationScope::~HeapIterationScope() {
@@ skipping 608 matching lines @@
   Dart::vm_isolate()->heap()->WriteProtect(false, include_code_pages_);
 }
 
 
 WritableVMIsolateScope::~WritableVMIsolateScope() {
   ASSERT(Dart::vm_isolate()->heap()->UsedInWords(Heap::kNew) == 0);
   Dart::vm_isolate()->heap()->WriteProtect(true, include_code_pages_);
 }
 
 }  // namespace dart