Revert "Remove IC age from Code."

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 7944d8a0fe3d17984fc77d0a6a969e30163e1f01..a103b0b39a5d8276eefed312b458c9e83002f745 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5057,6 +5057,11 @@ class Code: public HeapObject {
   // it is only used by the garbage collector itself.
   DECL_ACCESSORS(gc_metadata, Object)
 
+  // [ic_age]: Inline caching age: the value of the Heap::global_ic_age
+  // at the moment when this object was created.
+  inline void set_ic_age(int count);
+  inline int ic_age() const;
+
   // [prologue_offset]: Offset of the function prologue, used for aging
   // FUNCTIONs and OPTIMIZED_FUNCTIONs.
   inline int prologue_offset() const;
@@ -5412,15 +5417,17 @@ class Code: public HeapObject {
       kDeoptimizationDataOffset + kPointerSize;
   static const int kNextCodeLinkOffset = kTypeFeedbackInfoOffset + kPointerSize;
   static const int kGCMetadataOffset = kNextCodeLinkOffset + kPointerSize;
-  static const int kConstantPoolOffset = kGCMetadataOffset + kPointerSize;
-  static const int kInstructionSizeOffset = kConstantPoolOffset + kPointerSize;
-  static const int kFlagsOffset = kInstructionSizeOffset + kIntSize;
+  static const int kInstructionSizeOffset = kGCMetadataOffset + kPointerSize;
+  static const int kICAgeOffset = kInstructionSizeOffset + kIntSize;
+  static const int kFlagsOffset = kICAgeOffset + kIntSize;
   static const int kKindSpecificFlags1Offset = kFlagsOffset + kIntSize;
   static const int kKindSpecificFlags2Offset =
       kKindSpecificFlags1Offset + kIntSize;
   // Note: We might be able to squeeze this into the flags above.
   static const int kPrologueOffset = kKindSpecificFlags2Offset + kIntSize;
-  static const int kHeaderPaddingStart = kPrologueOffset + kIntSize;
+  static const int kConstantPoolOffset = kPrologueOffset + kIntSize;
+
+  static const int kHeaderPaddingStart = kConstantPoolOffset + kPointerSize;
 
   // Add padding to align the instruction start following right after
   // the Code object header.