Combine DEBUG_BREAK and DEBUG_PREPARE_STEP_IN into one IC stub kind DEBUG_STUB, encoding DEBUG_BREA…

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 658214a22996ef6186761787a3a55f85e6c60de0..f21355ec4be75ca2d4e738ae9fe3fc94e0f4aa8b 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3418,14 +3418,13 @@ InlineCacheState Code::ic_state() {
   // a call to code object has been replaced with a debug break call.
   ASSERT(is_inline_cache_stub() ||
          result == UNINITIALIZED ||
-         result == DEBUG_BREAK ||
-         result == DEBUG_PREPARE_STEP_IN);
+         result == DEBUG_STUB);
   return result;
 }
 
 
 Code::ExtraICState Code::extra_ic_state() {
-  ASSERT(is_inline_cache_stub());
+  ASSERT(is_inline_cache_stub() || ic_state() == DEBUG_STUB);
   return ExtractExtraICStateFromFlags(flags());
 }
 
@@ -3676,6 +3675,11 @@ bool Code::is_inline_cache_stub() {
 }
 
 
+bool Code::is_debug_break() {
+  return ic_state() == DEBUG_STUB && extra_ic_state() == DEBUG_BREAK;
+}
+
+
 Code::Flags Code::ComputeFlags(Kind kind,
                                InlineCacheState ic_state,
                                ExtraICState extra_ic_state,