Distinguish beween final incremental mark-compact and full mark-compact event in IdleNotification.

src/heap/gc-idle-time-handler.h

Index: src/heap/gc-idle-time-handler.h
diff --git a/src/heap/gc-idle-time-handler.h b/src/heap/gc-idle-time-handler.h
index e3a74627e56dd7da81fd3699cbae20c3bcfaa719..9b3b95e2c1ff58d17c6025fa49954335409eaa63 100644
--- a/src/heap/gc-idle-time-handler.h
+++ b/src/heap/gc-idle-time-handler.h
@@ -92,9 +92,18 @@ class GCIdleTimeHandler {
   // conservative lower bound for the mark-compact speed.
   static const size_t kInitialConservativeMarkCompactSpeed = 2 * MB;
 
+  // If we haven't recorded any final incremental mark-compact events yet, we
+  // use conservative lower bound for the mark-compact speed.
+  static const size_t kInitialConservativeFinalIncrementalMarkCompactSpeed =
+      2 * MB;
+
   // Maximum mark-compact time returned by EstimateMarkCompactTime.
   static const size_t kMaxMarkCompactTimeInMs;
 
+  // Maximum final incremental mark-compact time returned by
+  // EstimateFinalIncrementalMarkCompactTime.
+  static const size_t kMaxFinalIncrementalMarkCompactTimeInMs;
+
   // Minimum time to finalize sweeping phase. The main thread may wait for
   // sweeper threads.
   static const size_t kMinTimeForFinalizeSweeping;
@@ -128,6 +137,7 @@ class GCIdleTimeHandler {
     bool sweeping_in_progress;
     size_t mark_compact_speed_in_bytes_per_ms;
     size_t incremental_marking_speed_in_bytes_per_ms;
+    size_t final_incremental_mark_compact_speed_in_bytes_per_ms;
     size_t scavenge_speed_in_bytes_per_ms;
     size_t used_new_space_size;
     size_t new_space_capacity;
@@ -158,6 +168,9 @@ class GCIdleTimeHandler {
   static size_t EstimateMarkCompactTime(
       size_t size_of_objects, size_t mark_compact_speed_in_bytes_per_ms);
 
+  static size_t EstimateFinalIncrementalMarkCompactTime(
+      size_t size_of_objects, size_t mark_compact_speed_in_bytes_per_ms);
+
   static bool ShouldDoMarkCompact(size_t idle_time_in_ms,
                                   size_t size_of_objects,
                                   size_t mark_compact_speed_in_bytes_per_ms);
@@ -165,6 +178,10 @@ class GCIdleTimeHandler {
   static bool ShouldDoContextDisposalMarkCompact(bool context_disposed,
                                                  double contexts_disposal_rate);
 
+  static bool ShouldDoFinalIncrementalMarkCompact(
+      size_t idle_time_in_ms, size_t size_of_objects,
+      size_t final_incremental_mark_compact_speed_in_bytes_per_ms);
+
   static bool ShouldDoScavenge(
       size_t idle_time_in_ms, size_t new_space_size, size_t used_new_space_size,
       size_t scavenger_speed_in_bytes_per_ms,