Remove SealHandleScope from TryNumberToSize conversion

This function should also be callable from a concurrent thread, so we cannot use
the scope here. Instead, provide a test that checks that no handles are created.

R=ulan@chromium.org
TEST=cctest/test-conversions/NoHandlesForTryNumberToSize
BUG=

Review-Url: https://codereview.chromium.org/2106083002
Cr-Commit-Position: refs/heads/master@{#37381}

src/conversions-inl.h

@@ -133,7 +133,8 @@ int64_t NumberToInt64(Object* number) {
 }
 
 bool TryNumberToSize(Isolate* isolate, Object* number, size_t* result) {
-  SealHandleScope shs(isolate);
+  // Do not create handles in this function! Don't use SealHandleScope because
+  // the function can be used concurrently.
   if (number->IsSmi()) {
     int value = Smi::cast(number)->value();
     DCHECK(static_cast<unsigned>(Smi::kMaxValue) <=

test/cctest/test-conversions.cc

@@ -406,3 +406,30 @@ TEST(SpecialIndexParsing) {
   CheckNonArrayIndex(false, "-9999999999999999");
   CheckNonArrayIndex(false, "42949672964294967296429496729694966");
 }
+
+TEST(NoHandlesForTryNumberToSize) {
+  i::Isolate* isolate = CcTest::i_isolate();
+  size_t result = 0;
+  {
+    SealHandleScope no_handles(isolate);
+    Smi* smi = Smi::FromInt(1);
+    CHECK(TryNumberToSize(isolate, smi, &result));
+    CHECK_EQ(result, 1);
+  }
+  result = 0;
+  {
+    HandleScope scope(isolate);
+    Handle<HeapNumber> heap_number1 = isolate->factory()->NewHeapNumber(2.0);
+    {
+      SealHandleScope no_handles(isolate);
+      CHECK(TryNumberToSize(isolate, *heap_number1, &result));
+      CHECK_EQ(result, 2);
+    }
+    Handle<HeapNumber> heap_number2 = isolate->factory()->NewHeapNumber(
+        static_cast<double>(std::numeric_limits<size_t>::max()) + 10000.0);
+    {
+      SealHandleScope no_handles(isolate);
+      CHECK(!TryNumberToSize(isolate, *heap_number2, &result));
+    }
+  }
+}