Add Dart stack walker

runtime/vm/profiler.h

 // Copyright (c) 2013, 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_PROFILER_H_
 #define VM_PROFILER_H_
 
 #include "vm/allocation.h"
 #include "vm/code_observers.h"
 #include "vm/globals.h"
@@ skipping 215 matching lines @@
   }
 
   bool leaf_frame_is_dart() const {
     return LeafFrameIsDart::decode(state_);
   }
 
   void set_leaf_frame_is_dart(bool leaf_frame_is_dart) {
     state_ = LeafFrameIsDart::update(leaf_frame_is_dart, state_);
   }
 
+  bool ignore_sample() const {
+    return IgnoreBit::decode(state_);
+  }
+
+  void set_ignore_sample(bool ignore_sample) {
+    state_ = IgnoreBit::update(ignore_sample, state_);
+  }
+
   static void InitOnce();
 
   static intptr_t instance_size() {
     return instance_size_;
   }
 
   uword* GetPCArray() const;
 
  private:
   static intptr_t instance_size_;
   static intptr_t pcs_length_;
   enum StateBits {
     kProcessedBit = 0,
     kLeafFrameIsDartBit = 1,
+    kIgnoreBit = 2,
   };
   class ProcessedBit : public BitField<bool, kProcessedBit, 1> {};
   class LeafFrameIsDart : public BitField<bool, kLeafFrameIsDartBit, 1> {};
+  class IgnoreBit : public BitField<bool, kIgnoreBit, 1> {};
 
   int64_t timestamp_;
   ThreadId tid_;
   Isolate* isolate_;
   uword pc_marker_;
   uword vm_tag_;
   uword user_tag_;
   uword sp_;
   uword fp_;
   uword state_;
@@ skipping 53 matching lines @@
   intptr_t capacity_;
   uintptr_t cursor_;
 
   DISALLOW_COPY_AND_ASSIGN(SampleBuffer);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_PROFILER_H_