Oilpan: Enable HeapCompaction for incremental marking

Enables HeapCompaction for kIncrementalIdleGC and kIncrementalV8FollowupGC.

Bug: 864425

Change-Id: I1fb04d7c501a8519e106237946f86f52eb7ce8f8
Reviewed-on: https://chromium-review.googlesource.com/c/1297782Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603477}

third_party/blink/renderer/platform/heap/heap_compact.cc

@@ -367,14 +367,10 @@ bool HeapCompact::ShouldCompact(ThreadHeap* heap,
     return force_compaction_gc_;
   }
 
-  // TODO(keishi): Should be enable after fixing the crashes.
-  if (marking_type == BlinkGC::kIncrementalMarking)
-    return false;
-
-  // TODO(harukamt): Add kIncrementalIdleGC and kIncrementalV8FollowupGC when we
-  // enable heap compaction for incremental marking.
   if (reason != BlinkGC::GCReason::kIdleGC &&
       reason != BlinkGC::GCReason::kPreciseGC &&
+      reason != BlinkGC::GCReason::kIncrementalIdleGC &&
+      reason != BlinkGC::GCReason::kIncrementalV8FollowupGC &&
       reason != BlinkGC::GCReason::kForcedGC)
     return false;