[vm, gc] Require a safepoint for heap iteration.

runtime/vm/stack_frame_test.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/stack_frame.h"
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
@@ skipping 38 matching lines @@
 }
 
 void FUNCTION_NAME(StackFrame_frameCount)(Dart_NativeArguments args) {
   int count = 0;
   StackFrameIterator frames(StackFrameIterator::kValidateFrames,
                             Thread::Current(),
                             StackFrameIterator::kNoCrossThreadIteration);
   while (frames.NextFrame() != NULL) {
     count += 1;  // Count the frame.
   }
-  VerifyPointersVisitor::VerifyPointers();
+  {
+    TransitionNativeToVM transition(Thread::Current());
+    VerifyPointersVisitor::VerifyPointers();
+  }
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   arguments->SetReturn(Object::Handle(Smi::New(count)));
 }
 
 void FUNCTION_NAME(StackFrame_dartFrameCount)(Dart_NativeArguments args) {
   int count = 0;
   DartFrameIterator frames(Thread::Current(),
                            StackFrameIterator::kNoCrossThreadIteration);
   while (frames.NextFrame() != NULL) {
     count += 1;  // Count the dart frame.
   }
-  VerifyPointersVisitor::VerifyPointers();
+  {
+    TransitionNativeToVM transition(Thread::Current());
+    VerifyPointersVisitor::VerifyPointers();
+  }
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   arguments->SetReturn(Object::Handle(Smi::New(count)));
 }
 
 void FUNCTION_NAME(StackFrame_validateFrame)(Dart_NativeArguments args) {
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
 
   Dart_Handle index = Dart_GetNativeArgument(args, 0);
   Dart_Handle name = Dart_GetNativeArgument(args, 1);
@@ skipping 231 matching lines @@
         "  }"
         "}";
   }
   Dart_Handle lib = TestCase::LoadTestScript(
       kScriptChars, reinterpret_cast<Dart_NativeEntryResolver>(native_lookup));
   Dart_Handle cls = Dart_GetClass(lib, NewString("StackFrame2Test"));
   EXPECT_VALID(Dart_Invoke(cls, NewString("testMain"), 0, NULL));
 }
 
 }  // namespace dart