Fix a crash bug when creating a stack trace from an optimized frame.

runtime/vm/stack_frame.h

Index: runtime/vm/stack_frame.h
===================================================================
--- runtime/vm/stack_frame.h	(revision 17826)
+++ runtime/vm/stack_frame.h	(working copy)
@@ -229,17 +229,21 @@
 // Iterator for iterating over all inlined dart functions in an optimized
 // dart frame (the iteration includes the function that is inlining the
 // other functions).
-class InlinedFunctionsInDartFrameIterator : public ValueObject {
+class InlinedFunctionsIterator : public ValueObject {
  public:
-  explicit InlinedFunctionsInDartFrameIterator(StackFrame* frame);
-  RawFunction* GetNextFunction(uword* pc);
+  explicit InlinedFunctionsIterator(StackFrame* frame);
+  RawFunction* GetNextFunctionAndCode(uword* pc, Code* code);
 
  private:
   intptr_t index_;
+  Code& code_;
+  DeoptInfo& deopt_info_;
+  Function& function_;
+  uword pc_;
   GrowableArray<DeoptInstr*> deopt_instructions_;
   Array& object_table_;
 
-  DISALLOW_COPY_AND_ASSIGN(InlinedFunctionsInDartFrameIterator);
+  DISALLOW_COPY_AND_ASSIGN(InlinedFunctionsIterator);
 };
 
 }  // namespace dart