[heap] Introduce enum of garbage collection reasons.

test/cctest/heap/test-incremental-marking.cc

Index: test/cctest/heap/test-incremental-marking.cc
diff --git a/test/cctest/heap/test-incremental-marking.cc b/test/cctest/heap/test-incremental-marking.cc
index 643f7859b2e85901a00296ed4d94b28e06dc17f6..7ea35c11308bd5c8ad47f2ae22994b0ee07a28aa 100644
--- a/test/cctest/heap/test-incremental-marking.cc
+++ b/test/cctest/heap/test-incremental-marking.cc
@@ -122,7 +122,7 @@ TEST(IncrementalMarkingUsingIdleTasks) {
   i::heap::SimulateFullSpace(CcTest::heap()->old_space());
   i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
   marking->Stop();
-  marking->Start();
+  marking->Start(i::GarbageCollectionReason::kTesting);
   CHECK(platform.PendingIdleTask());
   const double kLongIdleTimeInSeconds = 1;
   const double kShortIdleTimeInSeconds = 0.010;
@@ -149,7 +149,7 @@ TEST(IncrementalMarkingUsingIdleTasksAfterGC) {
   MockPlatform platform(old_platform);
   i::V8::SetPlatformForTesting(&platform);
   i::heap::SimulateFullSpace(CcTest::heap()->old_space());
-  CcTest::heap()->CollectAllGarbage();
+  CcTest::CollectAllGarbage(i::Heap::kFinalizeIncrementalMarkingMask);
   // Perform any pending idle tasks.
   while (platform.PendingIdleTask()) {
     platform.PerformIdleTask(kLongIdleTimeInSeconds);
@@ -157,7 +157,7 @@ TEST(IncrementalMarkingUsingIdleTasksAfterGC) {
   CHECK(!platform.PendingIdleTask());
   i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
   marking->Stop();
-  marking->Start();
+  marking->Start(i::GarbageCollectionReason::kTesting);
   CHECK(platform.PendingIdleTask());
   const int kShortStepCount = 10;
   for (int i = 0; i < kShortStepCount && platform.PendingIdleTask(); i++) {
@@ -180,7 +180,7 @@ TEST(IncrementalMarkingUsingDelayedTasks) {
   i::heap::SimulateFullSpace(CcTest::heap()->old_space());
   i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
   marking->Stop();
-  marking->Start();
+  marking->Start(i::GarbageCollectionReason::kTesting);
   CHECK(platform.PendingIdleTask());
   // The delayed task should be a no-op if the idle task makes progress.
   const int kIgnoredDelayedTaskStepCount = 1000;