Merge flush code phase into marking phase.

src/frames.h

Index: src/frames.h
diff --git a/src/frames.h b/src/frames.h
index ef3011a8ffd0e8e76ecbefe5f89fc07083fca8c6..cb791d2d74c7ca9fff8f8cdccfbe01dc6467ca27 100644
--- a/src/frames.h
+++ b/src/frames.h
@@ -158,7 +158,13 @@ class StackFrame BASE_EMBEDDED {
   virtual Type type() const = 0;
 
   // Get the code associated with this frame.
-  virtual Code* code() const = 0;
+  // This method could be called during marking phase of GC.
+  virtual Code* unchecked_code() const = 0;
+
+  // Get the code associated with this frame.
+  inline Code* code() const {
+    return Code::cast(unchecked_code());
+  }
 
   // Garbage collection support.
   static void CookFramesForThread(ThreadLocalTop* thread);
@@ -224,7 +230,7 @@ class EntryFrame: public StackFrame {
  public:
   virtual Type type() const { return ENTRY; }
 
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   // Garbage collection support.
   virtual void Iterate(ObjectVisitor* v) const;
@@ -255,7 +261,7 @@ class EntryConstructFrame: public EntryFrame {
  public:
   virtual Type type() const { return ENTRY_CONSTRUCT; }
 
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   static EntryConstructFrame* cast(StackFrame* frame) {
     ASSERT(frame->is_entry_construct());
@@ -277,7 +283,7 @@ class ExitFrame: public StackFrame {
   enum Mode { MODE_NORMAL, MODE_DEBUG };
   virtual Type type() const { return EXIT; }
 
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   Object*& code_slot() const;
 
@@ -403,7 +409,7 @@ class JavaScriptFrame: public StandardFrame {
                      int index) const;
 
   // Determine the code for the frame.
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   static JavaScriptFrame* cast(StackFrame* frame) {
     ASSERT(frame->is_java_script());
@@ -439,7 +445,7 @@ class ArgumentsAdaptorFrame: public JavaScriptFrame {
   virtual Type type() const { return ARGUMENTS_ADAPTOR; }
 
   // Determine the code for the frame.
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   static ArgumentsAdaptorFrame* cast(StackFrame* frame) {
     ASSERT(frame->is_arguments_adaptor());
@@ -469,7 +475,7 @@ class InternalFrame: public StandardFrame {
   virtual void Iterate(ObjectVisitor* v) const;
 
   // Determine the code for the frame.
-  virtual Code* code() const;
+  virtual Code* unchecked_code() const;
 
   static InternalFrame* cast(StackFrame* frame) {
     ASSERT(frame->is_internal());