[heap] Remove obsolete AbortTracing calls and deprecate interface

V8 does not abort incremental marking anymore.

Bug: chromium:843903
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Id39e9cf8ef2afc388bab2bbad1d458ee2649f8e8
Reviewed-on: https://chromium-review.googlesource.com/1226889Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56009}

include/v8.h

@@ -7021,7 +7021,8 @@ class V8_EXPORT EmbedderHeapTracer {
    * The embedder is expected to throw away all intermediate data and reset to
    * the initial state.
    */
-  virtual void AbortTracing() = 0;
+  V8_DEPRECATE_SOON("Obsolete as V8 will not abort tracing anymore.",
+                    virtual void AbortTracing()) {}
 
   /*
    * Called by the embedder to request immediate finalization of the currently

src/heap/embedder-tracing.cc

@@ -24,13 +24,6 @@ void LocalEmbedderHeapTracer::TraceEpilogue() {
   remote_tracer_->TraceEpilogue();
 }
 
-void LocalEmbedderHeapTracer::AbortTracing() {
-  if (!InUse()) return;
-
-  cached_wrappers_to_trace_.clear();
-  remote_tracer_->AbortTracing();
-}
-
 void LocalEmbedderHeapTracer::EnterFinalPause() {
   if (!InUse()) return;
 

src/heap/embedder-tracing.h

@@ -36,7 +36,6 @@ class V8_EXPORT_PRIVATE LocalEmbedderHeapTracer final {
 
   void TracePrologue();
   void TraceEpilogue();
-  void AbortTracing();
   void EnterFinalPause();
   bool Trace(double deadline);
   bool IsRemoteTracingDone();

test/unittests/heap/embedder-tracing-unittest.cc

@@ -33,7 +33,6 @@ class MockEmbedderHeapTracer : public EmbedderHeapTracer {
  public:
   MOCK_METHOD0(TracePrologue, void());
   MOCK_METHOD0(TraceEpilogue, void());
-  MOCK_METHOD0(AbortTracing, void());
   MOCK_METHOD1(EnterFinalPause, void(EmbedderHeapTracer::EmbedderStackState));
   MOCK_METHOD0(IsTracingDone, bool());
   MOCK_METHOD1(RegisterV8References,
@@ -76,24 +75,6 @@ TEST(LocalEmbedderHeapTracer, TraceEpilogueForwards) {
   local_tracer.TraceEpilogue();
 }
 
-TEST(LocalEmbedderHeapTracer, AbortTracingForwards) {
-  StrictMock<MockEmbedderHeapTracer> remote_tracer;
-  LocalEmbedderHeapTracer local_tracer(nullptr);
-  local_tracer.SetRemoteTracer(&remote_tracer);
-  EXPECT_CALL(remote_tracer, AbortTracing());
-  local_tracer.AbortTracing();
-}
-
-TEST(LocalEmbedderHeapTracer, AbortTracingClearsCachedWrappers) {
-  StrictMock<MockEmbedderHeapTracer> remote_tracer;
-  LocalEmbedderHeapTracer local_tracer(nullptr);
-  local_tracer.SetRemoteTracer(&remote_tracer);
-  local_tracer.AddWrapperToTrace(CreateWrapperInfo());
-  EXPECT_CALL(remote_tracer, AbortTracing());
-  local_tracer.AbortTracing();
-  EXPECT_EQ(0u, local_tracer.NumberOfCachedWrappersToTrace());
-}
-
 TEST(LocalEmbedderHeapTracer, EnterFinalPauseForwards) {
   StrictMock<MockEmbedderHeapTracer> remote_tracer;
   LocalEmbedderHeapTracer local_tracer(nullptr);