Oilpan: Fix GCState transition checks

Fix GCState transition checks for when incrmental marking is enabled

Bug: 757440
Change-Id: I01cf15b45800d15bd50542824f64dd24d8e0ef0f
Reviewed-on: https://chromium-review.googlesource.com/991621Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547654}

third_party/WebKit/Source/platform/heap/ThreadState.cpp

@@ -755,6 +755,8 @@ void ThreadState::SetGCState(GCState gc_state) {
           gc_state_ == kNoGCScheduled || gc_state_ == kIdleGCScheduled ||
           gc_state_ == kPreciseGCScheduled || gc_state_ == kFullGCScheduled ||
           gc_state_ == kPageNavigationGCScheduled ||
+          gc_state_ == kIncrementalMarkingStartScheduled ||
+          gc_state_ == kIncrementalMarkingStepScheduled ||
           gc_state_ == kIncrementalMarkingFinalizeScheduled);
       break;
     case kIncrementalMarkingStartScheduled:
@@ -781,6 +783,8 @@ void ThreadState::SetGCState(GCState gc_state) {
       VERIFY_STATE_TRANSITION(
           gc_state_ == kNoGCScheduled || gc_state_ == kIdleGCScheduled ||
           gc_state_ == kIncrementalMarkingStartScheduled ||
+          gc_state_ == kIncrementalMarkingStepScheduled ||
+          gc_state_ == kIncrementalMarkingFinalizeScheduled ||
           gc_state_ == kPreciseGCScheduled || gc_state_ == kFullGCScheduled ||
           gc_state_ == kPageNavigationGCScheduled);
       CompleteSweep();