Force scavenge in idle notification if we estimate that it will take long.

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 473b4742d496d3d1baa5e69d1e12115d620630cb..16a1f948d31208affecd438958fcb41fce7e0d76 100644
--- a/src/heap/gc-idle-time-handler.h
+++ b/src/heap/gc-idle-time-handler.h
@@ -113,14 +113,18 @@ class GCIdleTimeHandler {
   // That is the maximum idle time we will have during frame rendering.
   static const size_t kMaxFrameRenderingIdleTime = 16;
 
+  // We consider idle notification with larger or equal invocations as large
+  // idle notifications.
+  static const size_t kLargeIdleTime = 10;
+
+  // Scavenges with a larger estimated execution time may be forced early by the
+  // idle notification.
+  static const size_t kForceScavengeThreshold = 10;
+
   // If less than that much memory is left in the new space, we consider it
   // as almost full and force a new space collection earlier in the idle time.
   static const size_t kNewSpaceAlmostFullTreshold = 100 * KB;
 
-  // If we haven't recorded any scavenger events yet, we use a conservative
-  // lower bound for the scavenger speed.
-  static const size_t kInitialConservativeScavengeSpeed = 100 * KB;
-
   struct HeapState {
     int contexts_disposed;
     size_t size_of_objects;
@@ -166,6 +170,15 @@ class GCIdleTimeHandler {
       size_t available_new_space_memory,
       size_t new_space_allocation_throughput_in_bytes_per_ms);
 
+  static bool DoEarlyScavenge(size_t idle_time_in_ms, size_t new_space_size,
+                              size_t available_new_space_memory,
+                              size_t scavenger_speed_in_bytes_per_ms);
+
+  static bool DoScavenge(
+      size_t idle_time_in_ms, size_t new_space_size,
+      size_t available_new_space_memory, size_t scavenger_speed_in_bytes_per_ms,
+      size_t new_space_allocation_throughput_in_bytes_per_ms);
+
  private:
   void StartIdleRound() { mark_compacts_since_idle_round_started_ = 0; }
   bool IsMarkCompactIdleRoundFinished() {