Optimize clearing of map transitions.

src/heap/gc-tracer.cc

Index: src/heap/gc-tracer.cc
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index 67bebdd37801ed49b73d8c25d0d8b895f8b20539..08f9e490179f8afe2de3a3de8c2c15b6c906d335 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -541,10 +541,10 @@ void GCTracer::PrintNVP() const {
                    "weakcollection_process=%.1f "
                    "weakcollection_clear=%.1f "
                    "weakcollection_abort=%.1f "
-                   "weakcells=%.1f "
-                   "nonlive_refs=%.1f "
-                   "extract_dependent_code=%.1f "
-                   "deopt_dependent_code=%.1f "
+                   "clear=%1f"
+                   "clear_weakcell=%.1f "
+                   "clear_map=%.1f "
+                   "clear_dependent_code=%.1f "
                    "steps_count=%d "
                    "steps_took=%.1f "
                    "longest_step=%.1f "
@@ -613,10 +613,10 @@ void GCTracer::PrintNVP() const {
                    current_.scopes[Scope::MC_WEAKCOLLECTION_PROCESS],
                    current_.scopes[Scope::MC_WEAKCOLLECTION_CLEAR],
                    current_.scopes[Scope::MC_WEAKCOLLECTION_ABORT],
-                   current_.scopes[Scope::MC_WEAKCELL],
-                   current_.scopes[Scope::MC_NONLIVEREFERENCES],
-                   current_.scopes[Scope::MC_EXTRACT_DEPENDENT_CODE],
-                   current_.scopes[Scope::MC_DEOPT_DEPENDENT_CODE],
+                   current_.scopes[Scope::MC_CLEAR],
+                   current_.scopes[Scope::MC_CLEAR_WEAKCELL],
+                   current_.scopes[Scope::MC_CLEAR_MAP],
+                   current_.scopes[Scope::MC_CLEAR_DEPENDENT_CODE],
                    current_.incremental_marking_steps,
                    current_.incremental_marking_duration,
                    current_.longest_incremental_marking_step,