[heap] Remove unused CompactionMode flag

R=ulan@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2493173003
Cr-Commit-Position: refs/heads/master@{#40925}

src/heap/incremental-marking.cc

@@ -519,9 +519,8 @@ void IncrementalMarking::StartMarking() {
         "[IncrementalMarking] Start marking\n");
   }
 
-  is_compacting_ = !FLAG_never_compact &&
-                   heap_->mark_compact_collector()->StartCompaction(
-                       MarkCompactCollector::INCREMENTAL_COMPACTION);
+  is_compacting_ =
+      !FLAG_never_compact && heap_->mark_compact_collector()->StartCompaction();
 
   state_ = MARKING;
 

src/heap/mark-compact.cc

@@ -274,8 +274,7 @@ static void TraceFragmentation(PagedSpace* space) {
          static_cast<int>(free), static_cast<double>(free) * 100 / reserved);
 }
 
-
-bool MarkCompactCollector::StartCompaction(CompactionMode mode) {
+bool MarkCompactCollector::StartCompaction() {
   if (!compacting_) {
     DCHECK(evacuation_candidates_.length() == 0);
 
@@ -823,7 +822,7 @@ void MarkCompactCollector::Prepare() {
   // Don't start compaction if we are in the middle of incremental
   // marking cycle. We did not collect any slots.
   if (!FLAG_never_compact && !was_marked_incrementally_) {
-    StartCompaction(NON_INCREMENTAL_COMPACTION);
+    StartCompaction();
   }
 
   PagedSpaces spaces(heap());

src/heap/mark-compact.h

@@ -431,9 +431,7 @@ class MarkCompactCollector {
   // Performs a global garbage collection.
   void CollectGarbage();
 
-  enum CompactionMode { INCREMENTAL_COMPACTION, NON_INCREMENTAL_COMPACTION };
-
-  bool StartCompaction(CompactionMode mode);
+  bool StartCompaction();
 
   void AbortCompaction();