Allow creating DartFrameIterator using explicit last_fp value (instead of always expecting it from …

runtime/vm/stack_frame.h

 // Copyright (c) 2011, 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_STACK_FRAME_H_
 #define VM_STACK_FRAME_H_
 
 #include "vm/allocation.h"
 #include "vm/object.h"
 #include "vm/stub_code.h"
@@ skipping 120 matching lines @@
 
 
 // Iterator for iterating over all frames from the last ExitFrame to the
 // first EntryFrame.
 class StackFrameIterator : public ValueObject {
  public:
   static const bool kValidateFrames = true;
   static const bool kDontValidateFrames = false;
 
   explicit StackFrameIterator(bool validate);
+  StackFrameIterator(uword last_fp, bool validate);
 
   // Checks if a next frame exists.
   bool HasNextFrame() const { return frames_.fp_ != 0; }
 
   // Get next frame.
   StackFrame* NextFrame();
 
  private:
   // Iterator for iterating over the set of frames (dart or stub) which exist
   // in one EntryFrame and ExitFrame block.
@@ skipping 46 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(StackFrameIterator);
 };
 
 
 // Iterator for iterating over all dart frames (skips over exit frames,
 // entry frames and stub frames).
 class DartFrameIterator : public ValueObject {
  public:
   DartFrameIterator() : frames_(StackFrameIterator::kDontValidateFrames) { }
-
+  explicit DartFrameIterator(uword last_fp)
+      : frames_(last_fp, StackFrameIterator::kDontValidateFrames) {}
   // Get next dart frame.
   StackFrame* NextFrame() {
     StackFrame* frame = frames_.NextFrame();
     while (frame != NULL && !frame->IsDartFrame()) {
       frame = frames_.NextFrame();
     }
     return frame;
   }
 
  private:
   StackFrameIterator frames_;
 
   DISALLOW_COPY_AND_ASSIGN(DartFrameIterator);
 };
 
 }  // namespace dart
 
 #endif  // VM_STACK_FRAME_H_