Change halfway-to-the-max GC trigger to measure committed pages, not allocated objects

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index b4fafec10939aea23ddd4bc2aada41fee52eced9..bbc2fedf1c3d19d7956a99100cd211404899bf88 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -41,7 +41,7 @@ MarkCompactCollector::MarkCompactCollector(Heap* heap)
       state_(IDLE),
 #endif
       reduce_memory_footprint_(false),
-      abort_incremental_marking_(false),
+      incremental_marking_abort_requested_(false),
       marking_parity_(ODD_MARKING_PARITY),
       compacting_(false),
       was_marked_incrementally_(false),
@@ -902,7 +902,7 @@ void MarkCompactCollector::Prepare() {
   }
 
   // Clear marking bits if incremental marking is aborted.
-  if (was_marked_incrementally_ && abort_incremental_marking_) {
+  if (was_marked_incrementally_ && incremental_marking_abort_requested_) {
     heap()->incremental_marking()->Abort();
     ClearMarkbits();
     AbortWeakCollections();
@@ -2183,11 +2183,12 @@ void MarkCompactCollector::ProcessTopOptimizedFrame(ObjectVisitor* visitor) {
 
 
 void MarkCompactCollector::RetainMaps() {
-  if (reduce_memory_footprint_ || abort_incremental_marking_ ||
+  if (reduce_memory_footprint_ || incremental_marking_abort_requested_ ||
       FLAG_retain_maps_for_n_gc == 0) {
     // Do not retain dead maps if flag disables it or there is
     // - memory pressure (reduce_memory_footprint_),
-    // - GC is requested by tests or dev-tools (abort_incremental_marking_).
+    // - GC is requested by tests or dev-tools
+    // (incremental_marking_abort_requested_).
     return;
   }